message: update to bool gripper API
diff: @@ -44,8 +44,7 @@ void gripperCommandExecuteCallback(
  return false;
  }
  if (goal->command.position >= state.width) {
  - gripper.move(goal->command.position, default_speed);
  - return true;
  + return gripper.move(goal->command.position, default_speed);
  }
  return gripper.grasp(goal->command.position, default_speed,
  goal->command.max_effort * newton_to_m_ampere_factor);
  @@ -71,19 +70,16 @@ void gripperCommandExecuteCallback(
  }
  bool move(const franka::Gripper& gripper, const MoveGoalConstPtr& goal) {
  - gripper.move(goal->width, goal->speed);
  - return true;
  + return gripper.move(goal->width, goal->speed);
  }
  bool homing(const franka::Gripper& gripper,
  const HomingGoalConstPtr& /*goal*/) {
  - gripper.homing();
  - return true;
  + return gripper.homing();
  }
  bool stop(const franka::Gripper& gripper, const StopGoalConstPtr& /*goal*/) {
  - gripper.stop();
  - return true;
  + return gripper.stop();
  }
  bool grasp(const franka::Gripper& gripper, const GraspGoalConstPtr& goal) {
  