[VRR] Add new frame rate settings APIs to ViewGruop

setPropagatedRequestedFrameRate: set frame rate on a ViewGruop and
propagate the frame rate value to all its children.

setRequestedFrameRate: set frame rate on a ViewGroup, but it won't
propagate to its children.

Bug: 374816285
Flag: android.view.flags.toolkit_viewgroup_set_requested_frame_rate_api
Test: new tests in ViewGroupTest
Change-Id: I11caa0dc8ade30573373167315c491ddec3d9e50