The new `layouts` preference replaces three previous preferences:
layout
second_layout
custom_layout
Add a preference migration function, which first migration is to
migrate layouts into the new preference.
The migration must also be called from the SettingsActivity as it might
use a different preference store due to the boot-aware preference copy.
setInputView() was not called when the view was re-created through
refresh_config(). Also, the refresh_config() function was not able to
properly set the current layout.
Now keep the default layout (_localeTextLayout) and the current non-text
layout (if any, _currentSpecialLayout) separately to be able to refresh
them later.
setInputView() is called everytime the view is created instead of by
onStartInputView() specifically.
The setting activity now save the preferences to the protected storage
in onStop() instead of listening for onSharedPreferenceChanged.
The callback might not be called if the "default" shared preferences is
different from the shared preferences actually used. This is unexpected
but seems to happen half of the time on Android 12.
Since f1ce6ab, this callback is critical to update the keyboard.
Restarting the application can no longer solve these issues.
Store preferences in device protected storage, which is available before
the device is unlocked.
The keyboard was crashing when trying to access the encrypted
preferences.
The emoji pane uses a separate preferences file, the old data is lost.
The SettingsActivity can't easily use the new preferences storage.
Instead, it continues to use the "default" preferences store, which is
copied back to the protected storage when needed.
There seems to be no "DayNight" theme compatible with older version of
android outside of the androidx library.
Using 'Theme.DeviceDefault' which is a dark theme, even if it doesn't
sounds like. Detect if a light theme should be used at activity
creation.
