[BUGFIX] Fix TypoScript object browser search

This fixes a couple of array key related PHP warnings,
triggered in the TypoScript object browser while searching.

This also fixes an error, leading to an empty search
result under some circumstances. A new acceptance
test is taking care, the search will always work
in the future.

Resolves: #95491
Resolves: #95494
Releases: master
Change-Id: Ifbd0aae5abf87ba455ea9d2acbf870cc830f652b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71464


Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>