Resource Handlers should return a 400 error instead of 500 when the problem is with the client request

HTTP ERROR 500 javax.servlet.ServletException: Failed to extract the Resource Reference from the URL [http://localhost:8080/xwiki/jcaptcha]
URI:	/xwiki/jcaptcha
STATUS:	500
MESSAGE:	javax.servlet.ServletException: Failed to extract the Resource Reference from the URL [http://localhost:8080/xwiki/jcaptcha]
SERVLET:	default
CAUSED BY:	javax.servlet.ServletException: Failed to extract the Resource Reference from the URL [http://localhost:8080/xwiki/jcaptcha]
CAUSED BY:	org.xwiki.resource.CreateResourceReferenceException: Invalid JCaptcha URL format [/]
Caused by:

javax.servlet.ServletException: Failed to extract the Resource Reference from the URL [http://localhost:8080/xwiki/jcaptcha]
	at org.xwiki.resource.servlet.ResourceReferenceHandlerServlet.getResourceReference(ResourceReferenceHandlerServlet.java:110)
	at org.xwiki.resource.servlet.ResourceReferenceHandlerServlet.service(ResourceReferenceHandlerServlet.java:87)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:590)
	at org.eclipse.jetty.servlet.ServletHolder$NotAsync.service(ServletHolder.java:1419)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:764)
	at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1624)
	at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFi