[TASK] Fix undefined array key error in ActionMenuItemViewHelper

The variable $this->arguments['selected'] is not always set.

Resolves: #95283
Releases: master
Change-Id: I24ac026300c04bd9bf2e5f2bab580cdf847df5ad
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71169


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>