Copy action displays Done even if copy/rename failed

As announced in XWIKI-14685 for XWiki 9, in XWiki 11.3.6 when the user doesn't have the rights to perform a copy, at the end of the process the message the message "Done" is displayed, even if the copy process failed.

To reproduce:

• On XWiki 11.3.6 Debian or Cloud
• Log out
• Go to any page and click the copy menu action (the fact that copy shouldn't be displayed at all is a different jira issue - XWIKI-14686)
• Select a target and click "copy"

Two problems with the result:

• It says "Done" even if the copy/rename fails.
• The new copy location page shows a non found page
• You cannot click on the error to know what was the problem.