[BUGFIX] Prevent including tsconfig absolute @import twice

Due to a missing file suffix check, @import for tsconfig was included
twice, while it was looping through the possible ".typoscript" an
".tsconfig" file suffixes. This is now fixed by making sure that the
absolute file name ends with the current file suffix.

Resolves: #100240
Related: #97816
Releases: main
Change-Id: I1f8acdddd60b257b93ce0ca21aee3434947fa999
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78200


Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>