[TASK] Remove dummy files from ext:workspaces

Change-Id: I631889db332b001da62d23d29401891746b223e2
Resolves: #47843
Related: #47756
Releases: 6.2
Reviewed-on: https://review.typo3.org/20434
Reviewed-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn