inputmethod: remove the workarounds
Do not set emit the enabledChanged of the text-input-v2 when it requests us to show input panel, it is already enabled when you get this request
If we get the request to show input panel, reset the inputContext, there's two reason we can get this event: 1) when keyboard focus is activated or 2) when keyboard focus is changed to text field in same surface. In both cases, information in input method context is not valid anymore and should be reset.
This also fixes the crash in maliit where it ends up working on outdated input method context because we changed the text field on same surface.
Code in 5.20 branch is slightly different but I'd like to do cherry-pick of the patch there as well.
CC: @jbbgameich can you please test this and ensure it fixes crash with maliit for you?