The PDF export file name is different when using the Docker container vs. the user browser

Follow these steps to reproduce:

• configure the PDF export to use the user's browser
• export Sandbox home page and save the PDF; the suggested file name is "Sandbox - XWiki.pdf"
• configure the PDF export to use the Docker container
• export again the Sandbox home page and save the PDF; the suggested file name is now "Sandbox.pdf"

The suggested file name should be the same no matter how the PDF was generated. Moreover, the file name suggested when using the user's browser doesn't respect the "fileName" PDF export job request parameter:

#set ($discard = $pdfExportJobRequest.setFileName('myCool.pdf'))