Merge pull request #32649 from qarmin/another_crash_fix_for_tile_map

Fix crash in TileMap::update_cell_bitmask

scene/2d/tile_map.cpp

@@ -955,6 +955,7 @@ void TileMap::update_bitmask_region(const Vector2 &p_start, const Vector2 &p_end
 
 void TileMap::update_cell_bitmask(int p_x, int p_y) {
 
+	ERR_FAIL_COND_MSG(tile_set.is_null(), "Cannot update cell bitmask if Tileset is not open.");
 	PosKey p(p_x, p_y);
 	Map<PosKey, Cell>::Element *E = tile_map.find(p);
 	if (E != NULL) {