Improve multi-user consistency in onFinishPackageChangesInternal()

With this CL we start applying the same logic among users when an APK
that provides the currently selected IME.

Previously we only updated the secure settings when called for
background users.

No abrupt observable behavior change is expected/intended.

Bug: 350386877
Flag: EXEMPT refactor
Test: manually verified
Change-Id: Ia03a9247e1ca9861e0921aac57dbeefbd0e56e57