[BUGFIX] Fix JavaScript error in configuration module

When performing a search in the configuration module,
a JavaScript error will occur, if a possible expanded
tree node is not part of the search result.

This patch adds checks for existence of the scrollElement
variable.

Resolves: #96097
Releases: master, 11.5
Change-Id: I5977dd48487563ae30407f8cf126724acc9bcb0a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72320


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