[BUGFIX] Correct open/close icon Included TypoScript

Site Management > TypoScript > Included TypoScript:
Show correct open / close triangle icon after load.

Resolves: #99686
Related: #99577
Related: #99576
Releases: main
Change-Id: I1f74fa34ad7233794f7f558476846506efaa627c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77541


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