Camera2/3: Properly disambiguate FPS range vs. single FPS setting

The camera1 API allows for either setPreviewFrameRate or
setPreviewFPSRange, so both values may or may not change in a single
setParameter call.

The disambiguation of which setting has been changed since the last
setParameter() call was not fully correct, so a sequence of changes
that only changed setPreviewFPSRange or didn't change either could be
interpreted as as a change to setPreviewFrameRate.

Bug: 10842868
Change-Id: I40baeced80a58f09f8a1742ece8dd5e141e9c1e3