[MIRROR] mass refactor of holder checks (#11155)

Co-authored-by: Kashargul <144968721+Kashargul@users.noreply.github.com>

code/game/objects/structures/artstuff.dm

@@ -541,7 +541,7 @@
  * For now, we do it this way because calling this on a canvas itself might cause issues due to the whole dimension thing.
 */
 /obj/structure/sign/painting/proc/admin_lateload_painting(var/spawn_specific = 0, var/which_painting = 0)
-	if(!usr.client.holder)
+	if(!check_rights_for(usr.client, R_HOLDER))
 		return 0
 	if(spawn_specific && isnum(which_painting))
 		var/list/painting = SSpersistence.all_paintings[which_painting]

code/game/objects/structures/props/machines.dm

@@ -640,7 +640,7 @@
 		return
 	if(!ismovable(AM))
 		return
-	if(!user.client?.holder)
+	if(!check_rights_for(user.client, R_HOLDER))
 		return
 	if(changing_state)
 		return