Exit the operator code if `DG_LOCK_WEIGHT` flag is set for active vertex group to avoid painting over locked vertex group. New function `BKE_object_defgroup_active_is_locked` created to handle this.
Exit the operator code if `DG_LOCK_WEIGHT` flag is set for active vertex group to avoid painting over locked vertex group. New function `BKE_object_defgroup_active_is_locked` created to handle this.