Add Toast logs and update docs

Some methods should not be called on text toasts rendered by the system
UI, adding logging and updating docs. Check go/toast-block-design for
details.

Bug: 128611929
Bug: 144754526
Test: Builds
Test: atest android.widget.cts29.ToastTest android.widget.cts.ToastTest
Change-Id: I282288afd0be604b2fdaa1348f09fc59e8f33d98