### Godot version

v4.0.beta11.official [91713ced8]

### System information

MX Linux 21

### Issue description

In Godot 3, TileMap had methods get_used_cells() and get_used_cells_by_id(). Godot 4's TileMap only has get_used_cells() and is missing get_used_cells_by_id().

get_used_cells_by_id() is highly useful in multiple cases, for example when trying to get all cells that are of road type, to randomly spawn a car.

Re-implementing get_used_cells_by_id() should be simple. The method could simply call get_used_cells(), and ignore all cells that are of the wrong ID.

### Steps to reproduce

N/A

### Minimal reproduction project

N/A
ERR_FAIL_COND(!tile_set.is_valid());
	ERR_FAIL_INDEX(p_layer, (int)layers.size());
	ERR_FAIL_INDEX(p_terrain_set, tile_set->get_terrain_sets_count());
	Vector<Vector2i> vector_path;
	HashSet<Vector2i> painted_set;
	for (int i = 0; i < p_path.size(); i++) {
		vector_path.push_back(p_path[i]);
		painted_set.insert(p_path[i]);
	}
	HashMap<Vector2i, TileSet::TerrainsPattern> terrain_fill_output = terrain_fill_path(p_layer, vector_path, p_terrain_set, p_terrain, p_ignore_empty_terrains);
	for (const KeyValue<Vector2i, TileSet::TerrainsPattern> &kv : terrain_fill_output) {
		if (painted_set.has(kv.key)) {
			
			TileMapCell c = tile_set->get_random_tile_from_terrains_pattern(p_terrain_set, kv.value);
			set_cell(p_layer, kv.key, c.source_id, c.get_atlas_coords(), c.alternative_tile);
		} else {
			
			TileSet::TerrainsPattern in_map_terrain_pattern = TileSet::TerrainsPattern(*tile_set, p_terrain_set);
			TileMapCell cell = get_cell(p_layer, kv.key);
			if (cell.source_id != TileSet::INVALID_SOURCE) {
				TileSetSource *source = *tile_set->get_source(cell.source_id);
				TileSetAtlasSource *atlas_source = Object::cast_to<TileSetAtlasSource>(source);
				if (atlas_source) {
					
					TileData *tile_data = atlas_source->get_tile_data(cell.get_atlas_coords(), cell.alternative_tile);
					if (tile_data && tile_data->get_terrain_set() == p_terrain_set) {
						in_map_terrain_pattern = tile_data->get_terrains_pattern();
					}