As the command only can be emmited in MDI mode, you will not be able to avoid that mode change in gmoccapy. I builded gmoccapy to listen to mode changes and that is why the GUI changes.
Why you are using a custom panel for G92 and not the macro button?
Or use the touch off part in the manual mode and edit that value.
If you still want to realize "not changing the GUI layout"
See the code in gmoccapy.py
on_hal_status_mode_mdi
I use there self.tool_change to avoid that change on a tool change.
You could use a python script to set this variable to True before executing your command and after the command set it again to False.
I have not done that, so you will have to find the solution and report how you did it
Norbert