[BUGFIX] Handle objects as key in DebuggerUtility

Due to the TYPO3\CMS\Core\Type\Map implementation,
the key of a collection entry can also be an object.

This is now handled properly in DebuggerUtility.

Resolves: #100655
Releases: main
Change-Id: I9d3a66e8cb08f369383297dcd80bc685ec03d6e1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78724


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Jochen <rothjochen@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>