Add Display.Mode.getAlternativeRefreshRates()

Add a method to Display.Mode to return all refresh rates
to which a seamless display mode switch can be done. Note
that this is not a hard guarantee for seamless switches,
but rather a guarantee that switching to any other mode
will be non seamless.

This is implemented using the config groups which we get
from SurfaceFlinger.

Bug: 161776429
Test: atest LocalDisplayAdapterTest
Change-Id: Id0e721f6c278ce9dcc04d59422b2f881a1154102