Observer GUI and log are missing when the controller is switched back

[mmurooka]

The following video shows switching controllers: BaselineWalkingController (BWC) -> MultiContactController (MCC) -> BWC.
After returning to BWC, Rviz's observer GUI is missing.

mc-rtc-observer-gui-disappear-after-controller-switch-20240507.mp4

[mmurooka]

Observer GUI is added (only) here

mc_rtc/src/mc_control/MCController.cpp

Line 624 in 418f74f

if(pipelineConfig("gui", false)) { pipeline.addToGUI(*gui()); }

and removed (only) here

mc_rtc/src/mc_control/mc_global_controller.cpp

Line 775 in 418f74f

if(controller_->gui_) { pipeline.removeFromGUI(*controller_->gui()); }

[mmurooka]

For the same reason, the observer's log is also missing even after the controller switches back.