### 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(!is_inside_tree());
	ERR_FAIL_COND(!tile_set.is_valid());
	Transform2D tilemap_xform = get_global_transform();
	SelfList<TileMapQuadrant> *q_list_element = r_dirty_quadrant_list.first();
	while (q_list_element) {
		TileMapQuadrant &q = *q_list_element->self();
		
		for (const KeyValue<Vector2i, Vector<RID>> &E : q.navigation_regions) {
			for (int i = 0; i < E.value.size(); i++) {
				RID region = E.value[i];
				if (!region.is_valid()) {
					continue;
				}
				NavigationServer2D::get_singleton()->region_set_map(region, RID());
			}
		}
		q.navigation_regions.clear();
		
		for (const Vector2i &E_cell : q.cells) {
			TileMapCell c = get_cell(q.layer, E_cell, true);
			TileSetSource *source;
			if (tile_set->has_source(c.source_id)) {
				source = *tile_set->get_source(c.source_id);
				if (!source->has_tile(c.get_atlas_coords()) || !source->has_alternative_tile(c.get_atlas_coords(), c.alternative_tile)) {
					continue;
				}
				TileSetAtlasSource *atlas_source = Object::cast_to<TileSetAtlasSource>(source);