### 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
HashMap<Vector2i, Vector<RID>> navigation_regions;
	
	HashMap<Vector2i, String> scenes;
	
	HashMap<Vector2i, TileData *> runtime_tile_data_cache;
	void operator=(const TileMapQuadrant &q) {
		layer = q.layer;
		coords = q.coords;
		debug_canvas_item = q.debug_canvas_item;
		canvas_items = q.canvas_items;
		occluders = q.occluders;
		bodies = q.bodies;
		navigation_regions = q.navigation_regions;
	}
	TileMapQuadrant(const TileMapQuadrant &q) :
			dirty_list_element(this) {
		layer = q.layer;
		coords = q.coords;
		debug_canvas_item = q.debug_canvas_item;
		canvas_items = q.canvas_items;
		occluders = q.occluders;
		bodies = q.bodies;
		navigation_regions = q.navigation_regions;
	}
	TileMapQuadrant() :
			dirty_list_element(this) {
	}
};
class TileMap : public Node2D {