fix(magnify_ime): Fix mag toggle visibility for window-only mode

In window-only mode we want:
- Magnify keyboard invisible
- Follow typing visible

This aligns with the Settings app behavior.

Fix: 413441693
Fix: 417876117
Test: atest WindowMagnificationSettingsTest
Flag: com.android.server.accessibility.enable_magnification_magnify_nav_bar_and_ime
Change-Id: Ieef43ec488528909e77ab9b56cbedfac5813671e