[TASK] Extend RequestToken tests

Added tests for malformed JWT-like literals.

Resolves: #98473
Related: #97305
Releases: main
Change-Id: Ida62075c4bf9480d208ee1ca77b010c0559b025f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75913


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Torben Hansen <derhansen@gmail.com>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>