Fix the velocity smoother being stuck when the deadband is too high (r…

…os-navigation#3690)

* Move last_cmd update before deadband

* fix lint

nav2_velocity_smoother/src/velocity_smoother.cpp

@@ -305,13 +305,14 @@ void VelocitySmoother::smootherTimer()
  current_.linear.y, command_->linear.y, max_accels_[1], max_decels_[1], eta);
  cmd_vel->angular.z = applyConstraints(
  current_.angular.z, command_->angular.z, max_accels_[2], max_decels_[2], eta);
+ last_cmd_ = *cmd_vel;
 
  // Apply deadband restrictions & publish
  cmd_vel->linear.x = fabs(cmd_vel->linear.x) < deadband_velocities_[0] ? 0.0 : cmd_vel->linear.x;
  cmd_vel->linear.y = fabs(cmd_vel->linear.y) < deadband_velocities_[1] ? 0.0 : cmd_vel->linear.y;
  cmd_vel->angular.z = fabs(cmd_vel->angular.z) <
  deadband_velocities_[2] ? 0.0 : cmd_vel->angular.z;
- last_cmd_ = *cmd_vel;
+
  smoothed_cmd_pub_->publish(std::move(cmd_vel));
 }