(Almost) display active priority mode icon in status bar

This updates StatusBarIconController, StatusBarIcon, and StatusBarIconView to support:
* resources from non-system packages.
* preloaded drawables for said resources (in case an existing cache exists, as in the case of modes).

Some things are pending:
* Icons are not the correct ones for "special" modes (Do Not Disturb shows the TYPE_OTHER icon). This needs some (relatively minor) changes in ZenIconLoader & friends.
* Preloaded icons are not tinted correctly on theme changes.
* Resource-id icons are tinted correctly, but arbitrarily-sized ones are not resized correctly. ¯\_(ツ)_/¯

Bug: 360399800
Test: atest StatusBarIconControllerImplTest PhoneStatusBarPolicyTest StatusBarIconViewTest StatusBarIconTest
Flag: android.app.modes_ui
Change-Id: I3fc3815895953c401c426d6eebcb9e4c83c95726