SF: Stop forcing modeset on fold/unfold

SF no longer needs to defer setDesiredDisplayModeSpecs for the inactive
display until it becomes active on fold/unfold, because it now supports
per-display modeset since I9da3a0be07f9fbb08f11485aa6ab9400259a4e09.

Remove SF::shouldApplyRefreshRateSelectorPolicy, which was used to skip
applying DM's policy while a display is powered off. Though it had also
been used to skip SF::requestDisplayModes in response to changes in the
Scheduler's policy, I4dd954bf9a943f181bd64950ff9edee863f53e99 suppressed
those calls in the Scheduler.

Bug: 255635711
Bug: 255635821
Flag: NONE (blocks P1 bug fix, and perf risk is limited to foldables)
Test: Watch refresh rate overlay for MRR CUJs plus folding/unfolding.
Test: DisplayModeSwitchingTest
Change-Id: Ia5afb75977249fc734bd78625d8ffd4c433a3a8d