Clean up flag notification_async_hybrid_view_inflation 2

The impact of this flag is particularly wide, so breaking down the flag
removal by method for code robustness and easier review. This change
cleans the legacy codes.

Clean up flag:
com.android.systemui.notification_async_hybrid_view_inflation

Bug: 409612328
Test: SingleLineViewInflaterTest, SingleLineViewBinderTest,
NotifUiAdjustmentProviderTest
Flag: EXEMPT flag cleanup

Change-Id: I96e854073f63b1436265eebc83790eac8dd88a15