### 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
if (in_top_left_triangle) {
						ret += Vector2i(-1, 0);
					} else if (in_bottom_left_triangle) {
						ret += Vector2i(-1, 1);
					}
					break;
				case TileSet::TILE_LAYOUT_DIAMOND_RIGHT:
					ret = Vector2(ret.x / 2 - ret.y, ret.y + ret.x / 2).floor();
					if (in_top_left_triangle) {
						ret += Vector2i(0, -1);
					} else if (in_bottom_left_triangle) {
						ret += Vector2i(-1, 0);
					}
					break;
				case TileSet::TILE_LAYOUT_DIAMOND_DOWN:
					ret = Vector2(ret.x / 2 + ret.y, ret.y - ret.x / 2).floor();
					if (in_top_left_triangle) {
						ret += Vector2i(-1, 0);
					} else if (in_bottom_left_triangle) {
						ret += Vector2i(0, 1);
					}
					break;
			}
		}
	} else {
		ret = (ret + Vector2(0.00005, 0.00005)).floor();
	}
	return Vector2i(ret);
}
bool TileMap::is_existing_neighbor(TileSet::CellNeighbor p_cell_neighbor) const {