camera2: Skip AF state updates when afMode/afState are missing

* Workaround for hal3 sometimes dropping afMode/afState (rarely)
  - don't update AF states, instead just skip this frame, safer
    and adds 1 frame of latency very rarely sometimes.

* Assumes request is repeating, since otherwise we wouldn't get future
  af transition results

Bug: 11238865
Change-Id: Ic793d8c6d44873f6a7983e84e4510b8587a148a0