Add unit test to test execution for grouped workspace re #6983

This unit test currently fails.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Fix bug throwing exception for group workspaces re #6983

This required moving setProperty("OutputWorkspace", inputWS) within RenameWorkspace::processGroups().

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge branch 'feature/6983_rename_workspaces' into develop