This also removes the GROUP/UNGROUP-specific undo actions.
This also fixes a bunch of undo bugs when duplicating
group members, creating pins, etc.
This also fixes some undo bugs when dividing wires etc.
This also fixes some bugs with new sch items not
being created within an entered group.
There was a similar issue in Pcbnew, fixed in PCB_GROUP::swapData() by commit
fc969ae50110585c555f598855a70f564e529e26
So apply the same fix to SCH_GROUP::swapData()