[TASK] Improve file rename duplicate warning message

Improve the warning message presented to the user when a file is renamed
through the Filelist module and a file with the new name already exists.

Resolves: #91299
Releases: master
Change-Id: If1ff921396f782c1f560fdb092755e306344d0f3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64427


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: Benjamin Franzke <bfr@qbus.de>