Clowncar exploit fix (#43237)

Fixed an exploit allowing you to grab people from anywhere with a clowncar.

code/modules/vehicles/cars/car.dm

@@ -78,11 +78,15 @@
 		return FALSE
 	if(occupant_amount() >= max_occupants)
 		return FALSE
-	if(do_mob(forcer, get_enter_delay(M), target = src))
+	var/atom/old_loc = loc
+	if(do_mob(forcer, M, get_enter_delay(M), extra_checks=CALLBACK(src, /obj/vehicle/sealed/car/proc/is_car_stationary, old_loc)))
 		mob_forced_enter(M, silent)
 		return TRUE
 	return FALSE
 
+/obj/vehicle/sealed/car/proc/is_car_stationary(atom/old_loc)
+	return (old_loc == loc)
+
 /obj/vehicle/sealed/car/proc/mob_forced_enter(mob/M, silent = FALSE)
 	if(!silent)
 		M.visible_message("<span class='warning'>[M] is forced into \the [src]!</span>")