Fix NoSuchElementException is threw when unlinkToDeath is called

Parameter flags in Binder::linkToDeath must be matched as a pair
with the recipient in unlinkToDeath to be removed from mObituaries
and deleted.
Since each service's cookie list meaningfully starts from 1,
setting the flag to 0 in unlinkToDeath is equivalent to not to
find an existing recipient in mObituaries.
Therefore, for truly unlinking, use the flag set in the linkToDeath
again to unlink it and remove it from the binder.

Bug: 340156301
Test: Basic telephony funcationlity tests
Test: atest FrameworksTelephonyTests
Change-Id: Ib1172bc8cdbfc8d6f42474c8e2adffe3f92af3b3