Clean up PIC test calls

In PropertyInvalidatedCache, getDisabledState() is just a call to
isDisabled().  This change replaces all calls to getDisabledState()
with a call to isDisabled(), in preparation for removing the obsolete
test api.

Flag: EXEMPT refactor
Bug: 385198070
Test: atest
 * FrameworksCoreTests:PropertyInvalidatedCacheTests
 * FrameworksCoreTests:IpcDataCacheTest
 * CtsOsTestCases:IpcDataCacheTest
Change-Id: I65e5ac23b1889120840f90e50dad26797473e4b1