[dVRR] Remove idle handling logic in ViewRootImpl

Remove idle handling logic in ViewRootImpl since SurfaceFling already
handles it.

Bug: 334329455
Test: atest ViewRootImplTest / atest ViewFrameRateTest
Change-Id: Ia35d94507100db39c0d850c7e68a1829c2d5fbf5
2 files changed