[MIRROR] converts area booleans to flags (#9595)

Co-authored-by: Heroman3003 <31296024+Heroman3003@users.noreply.github.com>
Co-authored-by: Kashargul <144968721+Kashargul@users.noreply.github.com>

code/modules/mob/dead/observer/observer.dm

@@ -196,7 +196,7 @@ Works together with spawning an observer, noted above.
 	if(!isturf(loc))
 		return
 	var/area/A = get_area(src)
-	if(A.block_ghosts)
+	if(A.flag_check(AREA_BLOCK_GHOSTS))
 		to_chat(src, span_warning("Ghosts can't enter this location."))
 		return_to_spawn()
 
@@ -454,7 +454,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 
 	//RS Port #658 Start
 	var/area/A = get_area(destination)
-	if(A.block_ghosts)
+	if(A.flag_check(AREA_BLOCK_GHOSTS))
 		to_chat(src,span_warning("Sorry, that area does not allow ghosts."))
 		if(following)
 			stop_following()