Align controlled_frame field in feedback with design (#8)

According to [the design document](https://github.com/fzi-forschungszentrum-informatik/fzi_robot_interface_proposal/blob/01a9c14a456fb76ccc6dd158a9cb0573a9ebb2da/source/proposal/index.rst#L237), the action feedback should contain a field called `controlled_frame`.`tcp_frame` was the old name, prior to renaming it to `controlled_frame`.

Co-authored-by: G.A. vd. Hoorn <[email protected]>

Author: fmauch

action/FollowCartesianTrajectory.action

@@ -19,7 +19,7 @@ string error_string
 ---
 
 std_msgs/Header header
-string tcp_frame
+string controlled_frame
 CartesianTrajectoryPoint desired
 CartesianTrajectoryPoint actual
 CartesianTrajectoryPoint error