[TASK] Use CPP in ModifyButtonBarEvent

With this change, CPP is used in ModifyButtonBarEvent.

Resolves: #101762
Releases: main
Signed-off-by: Torben Hansen <derhansen@gmail.com>
Change-Id: Iaf3988df3ad2d47f1b10c08fe85a040b5a2ea676
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80702


Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>