### 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
TerrainConstraint terrain_bit_constraint = TerrainConstraint(this, p_position, bit, terrain_pattern.get_terrain_peering_bit(bit));
				in_set_constraint_element = p_constraints.find(terrain_bit_constraint);
				if (in_set_constraint_element) {
					if (in_set_constraint_element->get().get_terrain() != terrain_bit_constraint.get_terrain()) {
						score += in_set_constraint_element->get().get_priority();
					}
				} else if (p_current_pattern.get_terrain_peering_bit(bit) != terrain_pattern.get_terrain_peering_bit(bit)) {
					invalid_pattern = true; 
					break;
				}
			}
		}
		if (invalid_pattern) {
			continue;
		}
		terrain_pattern_score[terrain_pattern] = score;
	}
	
	TileSet::TerrainsPattern min_score_pattern = p_current_pattern;
	int min_score = INT32_MAX;
	for (KeyValue<TileSet::TerrainsPattern, int> E : terrain_pattern_score) {
		if (E.value < min_score) {
			min_score_pattern = E.key;
			min_score = E.value;
		}
	}
	return min_score_pattern;
}
RBSet<TileMap::TerrainConstraint> TileMap::_get_terrain_constraints_from_added_pattern(const Vector2i &p_position, int p_terrain_set, TileSet::TerrainsPattern p_terrains_pattern) const {