I wouldn't recommend this approach. You shouldn't have to create extra users to do what you want. Also, changing from one user to another in the app isn't supported. (You would need to remove the account, then re-add it with the new username, which will download the correct data for the new user.)
I would just go ahead and send the MIDI data for both pedals all the time, and the data for the pedal that isn't connected won't go anywhere or do anything.
If you're concerned about that, you could deactivate one MIDI device or another depending on what pedal is present, assuming you already set up a MIDI device for each pedal.