Disable some calls to on_presets_changed to speed up switching profiles

By profiling I found that most of the time switching profiles is spent in calls to on_presets_changed, rebuilding the presets list.

I tried turning off 2 points in the code that seem to be responsible for most of it. I hope they're not important to keep. It seems to help a lot - I now get around 2 seconds to swap or save profiles, instead of 27, with profiling on.