Disable pose broadcaster on mock hardware (UniversalRobots#1229)

As mock hardware doesn't send the same pose information as the real robot does, it does make sense to not start it in mock hardware.

ur_robot_driver/launch/ur_control.launch.py

@@ -183,6 +183,9 @@ def controller_spawner(controllers, active=True):
         controllers_active.append(initial_joint_controller.perform(context))
         controllers_inactive.remove(initial_joint_controller.perform(context))
 
+    if use_mock_hardware.perform(context) == "true":
+        controllers_active.remove("tcp_pose_broadcaster")
+
     controller_spawners = [
         controller_spawner(controllers_active),
         controller_spawner(controllers_inactive, active=False),