[CDM] Fix race condition that caused handshake init collision detection to be...

[CDM] Fix race condition that caused handshake init collision detection to be bypassed occasionally.

Bug: 390216902
Test: Manual test
Test: atest CtsWearableSensingServiceTestCases:android.wearable.cts.WearableSensingManagerIsolatedServiceTest#provideConnection_allowConcurrent_canReceiveDataInWss --rerun-until-failure 100
Flag: EXEMPT bug fix
Change-Id: I005dd637b215593898af2b8cde22c6e005c4802e