### 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
bool collision_animatable = false;
	VisibilityMode collision_visibility_mode = VISIBILITY_MODE_DEFAULT;
	VisibilityMode navigation_visibility_mode = VISIBILITY_MODE_DEFAULT;
	
	bool pending_update = false;
	
	Rect2 rect_cache;
	bool rect_cache_dirty = true;
	Rect2i used_rect_cache;
	bool used_rect_cache_dirty = true;
	
	struct TileMapLayer {
		String name;
		bool enabled = true;
		Color modulate = Color(1, 1, 1, 1);
		bool y_sort_enabled = false;
		int y_sort_origin = 0;
		int z_index = 0;
		RID canvas_item;
		HashMap<Vector2i, TileMapCell> tile_map;
		HashMap<Vector2i, TileMapQuadrant> quadrant_map;
		SelfList<TileMapQuadrant>::List dirty_quadrant_list;
	};
	LocalVector<TileMapLayer> layers;
	int selected_layer = -1;
	
	HashMap<RID, Vector2i> bodies_coords;
	
	Vector2i _coords_to_quadrant_coords(int p_layer, const Vector2i &p_coords) const;
	HashMap<Vector2i, TileMapQuadrant>::Iterator _create_quadrant(int p_layer, const Vector2i &p_qk);