[TASK] Cleanup of type for sameBeginEnd in ContentObjectRenderer

The variable sameBeginEnd should have the type bool, since the
comparison calculation yields a bool.

Resolves: #99776
Releases: main, 11.5
Change-Id: Iddbd04197b1b2f99bc96d365c0c4dde1615568da
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77580


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>