Make more methods in IMMS multi-user aware

With this CL the following IMMS methods become multi-user aware.

 * chooseNewDefaultIMELocked
 * resetSelectedInputMethodAndSubtypeLocked
 * updateDefaultVoiceImeIfNeededLocked
 * setInputMethodEnabledLocked

This is a mechanical refactoring CL. There must be no observable
behavior change.

Bug: 350386877
Test: presubmit
Flag: android.view.inputmethod.concurrent_input_methods
Change-Id: I0010ab8c930c5d697227ef107264dadaea398881