### 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
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 (is_existing_neighbor(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);
				}
			}
		}
	}
	
	RBSet<Vector2i> cells_with_terrain_center_bit;
	for (Vector2i coords : can_modify_set) {
		bool connect = false;
		if (painted_set.has(coords)) {
			connect = true;
		} else {
			
			TileData *tile_data = nullptr;
			TileMapCell cell = get_cell(p_layer, coords);