[BUGFIX] Fix Undefined array key error in PHP8 for EXT:workspaces

Will fix creation/edit content as well as publishing
workflow for workspaces and add a basic ac test
for page change, switch workspace and publish

Also EXT:workspaces is now enabled in test environment

Resolves: #94361
Releases: master
Change-Id: I9f85a4edaa90e77cbdfc5f988007917263ed51ce
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69508


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>