### 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
}
	
	output = terrain_fill_constraints(p_layer, can_modify_list, p_terrain_set, constraints);
	return output;
}
HashMap<Vector2i, TileSet::TerrainsPattern> TileMap::terrain_fill_pattern(int p_layer, const Vector<Vector2i> &p_coords_array, int p_terrain_set, TileSet::TerrainsPattern p_terrains_pattern, bool p_ignore_empty_terrains) {
	HashMap<Vector2i, TileSet::TerrainsPattern> output;
	ERR_FAIL_COND_V(!tile_set.is_valid(), output);
	ERR_FAIL_INDEX_V(p_terrain_set, tile_set->get_terrain_sets_count(), output);
	
	Vector<Vector2i> can_modify_list;
	RBSet<Vector2i> can_modify_set;
	RBSet<Vector2i> painted_set;
	for (int i = p_coords_array.size() - 1; i >= 0; i--) {
		const Vector2i &coords = p_coords_array[i];
		can_modify_list.push_back(coords);
		can_modify_set.insert(coords);
		painted_set.insert(coords);
	}
	for (Vector2i coords : p_coords_array) {
		
		for (int j = 0; j < TileSet::CELL_NEIGHBOR_MAX; j++) {
			TileSet::CellNeighbor bit = TileSet::CellNeighbor(j);
			if (tile_set->is_valid_terrain_peering_bit(p_terrain_set, bit)) {
				Vector2i neighbor = get_neighbor_cell(coords, bit);
				if (!can_modify_set.has(neighbor)) {
					can_modify_list.push_back(neighbor);
					can_modify_set.insert(neighbor);
				}
			}