Emoji characters break PDF export

SystemId Unknown; Line #7; Column #105; Character reference "&#55357" is an invalid XML character.
[Fatal Error] :-1:-1: Premature end of file.
2020-03-09 16:01:54,006 [http://localhost:9293/xwiki/bin/export/Sandbox/Foo/WebHome?format=pdf&pdfcover=0&pdftoc=0&pdfheader=0&pdffooter=0&comments=0&attachments=0] WARN  c.x.x.w.XWikiAction            - Uncaught exception: Error number 11015 in 11: Exception while exporting 
com.xpn.xwiki.XWikiException: Error number 11015 in 11: Exception while exporting
	at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:94)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:560)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:250)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder$NotAsyncServlet.service(ServletHolder.java:1401)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:760)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1617)
	at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:112)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
	at org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:109)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
	at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
	at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
	at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
	at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:132)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1596)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:536)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1592)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1296)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1562)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1211)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.Server.handle(Server.java:500)
	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:386)
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:562)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:378)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:388)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
	at java.lang.Thread.run(Thread.java:748)
Caused by: com.xpn.xwiki.XWikiException: Error number 12002 in 12: Exception while exporting pdf
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.createException(PdfExportImpl.java:524)
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.renderXSLFO(PdfExportImpl.java:262)
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportXHTML(PdfExportImpl.java:220)
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportHtml(PdfExportImpl.java:173)
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.export(PdfExportImpl.java:159)
	at com.xpn.xwiki.web.ExportAction.export(ExportAction.java:184)
	at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:91)
	... 56 common frames omitted
Caused by: javax.xml.transform.TransformerException: org.xml.sax.SAXParseException; Premature end of file.
	at org.apache.xalan.transformer.TransformerIdentityImpl.transform(TransformerIdentityImpl.java:502)
	at com.xpn.xwiki.internal.pdf.FOPXSLFORenderer.render(FOPXSLFORenderer.java:145)
	at com.xpn.xwiki.pdf.impl.PdfExportImpl.renderXSLFO(PdfExportImpl.java:258)
	... 61 common frames omitted
Caused by: org.xml.sax.SAXParseException: Premature end of file.
	at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
	at org.apache.xalan.transformer.TransformerIdentityImpl.transform(TransformerIdentityImpl.java:485)
	... 63 common frames omitted