[le audio] Fix bis sync state parsing with 0xFFFFFFFF

If the state is failed to sync to BIG(0xFFFFFFFF), our current parsing logic will
return -1 with getBisSyncState.
We should return 0xFFFFFFFF with long type.

Bug: 362578559
Test: atest BassClietStateMachineTest UtilsTest
Flag: Exempt; trivial change covered with unit tests
Change-Id: I1b5b6039aff776ef0a92f5d19ea2647594cdb70a