[TASK] Remove EXT:lang FormEngineBasedCheckboxGroupViewHelper

Remove EXT:lang FormEngineBasedCheckboxGroupViewHelper this
is not used anymore in the core.

Resolves: #44527
Releases: 6.1, 6.0

Change-Id: I06925b20d7399181be6bb2d5f5439cade1fca7c1
Reviewed-on: https://review.typo3.org/17540
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Oliver Klee
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn