Remove controller switch to passthrough controller (#1857)

The way it was implemented right now, the test was flakey, since it
didn't wait for the passthrough controller to be loaded. This way, it
could happen that the switch command was called while the CM didn't even
know the passthrough controller resulting in the service call failing.

Switching the controller shouldn't be necessary for the test, anyway, so
it is removed in this commit.

Author: urfeex

ur_robot_driver/test/integration_test_hand_back_control.py

@@ -38,7 +38,6 @@
 import pytest
 import rclpy
 from control_msgs.action import FollowJointTrajectory
-from controller_manager_msgs.srv import SwitchController
 from rclpy.node import Node
 from std_msgs.msg import Bool
 
@@ -166,13 +165,6 @@ def program_state_cb(msg):
         self._controller_manager_interface.wait_for_controller(
             "joint_trajectory_controller", "active"
         )
-        self.assertTrue(
-            self._controller_manager_interface.switch_controller(
-                strictness=SwitchController.Request.BEST_EFFORT,
-                deactivate_controllers=["passthrough_trajectory_controller"],
-                activate_controllers=["joint_trajectory_controller"],
-            ).ok
-        )
 
         self.assertTrue(
             external_control_running, "Robot program should be running before hand_back_control"