Ensure setRequestedOrientation is called when unfolding the device

- In RotationHelper, mLastActivityFlags defaults to -1, which is the same value as SCREEN_ORIENTATION_UNSPECIFIED. When the screen is folded, a new instance of RotationHelper is created, which attempts to reset setRequestedOrientation to SCREEN_ORIENTATION_UNSPECIFIED. But SCREEN_ORIENTATION_UNSPECIFIED is equal to mLastActivityFlags, and the call is skipped.
- The simpel fix is to default mLastActivityFlags to something else that is not a a valid value of setRequestedOrientation

Bug: 177320461
Change-Id: I1ca284149598745bfa612ee12e4da3b940b60288
(cherry picked from commit 8aa592f44620a8f57fa104819f8bba57c4360f95)