Merge pull request #62632 from linkpy/62630_fix

Make sure the tile data clears its `terrain` field when said terrain is removed from the tileset.

scene/resources/tile_set.cpp

@@ -4924,6 +4924,10 @@ void TileData::move_terrain(int p_terrain_set, int p_from_index, int p_to_pos) {
 
 void TileData::remove_terrain(int p_terrain_set, int p_index) {
 	if (terrain_set == p_terrain_set) {
+		if (terrain == p_index) {
+			terrain = -1;
+		}
+
 		for (int i = 0; i < 16; i++) {
 			if (terrain_peering_bits[i] == p_index) {
 				terrain_peering_bits[i] = -1;