Report freezable state changes only if there is a change.

CachedAppOptimizer.unfreezeAppLSP() could be called even if the
process is not frozen and unfreezeAppLSP() returns early if the
process is not frozen. So, reportProcessFreezableChangedLocked()
should only be called after unfreezeAppLSP() checks if there is
a need to do any unfreezing.

Bug: 301986056
Test: atest CtsBroadcastTestCases
Change-Id: I6b50aac1d24f02fd1d84a095ba487fea80f9091a