[BUGFIX] Do not call getConflictingRedirects with null request

Resolves: #100827
Releases: main, 12.4
Change-Id: I2c553894af4b25c2f4731782f0d9cf2293ec3211
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78958


Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>