Revert resetting density and configs on exiting PiP.

Resetting the density causes some unexpected Core config changes that
makes multiple binder calls and causes the app to malfunction upon
launching an app while it's in PiP on another display.

Fixes: 443007642
Flag: com.android.window.flags.enable_dragging_pip_across_displays
Test: atest ActivityRecordTests
Change-Id: I1afde7e0659a3db6e4fbacbea7b9433b7aff6eb4