Refactor out originalClientPid in connectHelper.

connectHelper enlists validateConnectLocked / validateClientPermissionsLocked
to return the "originalClientPid" and set clientPid to the calling pid.
Removing this parameter simplifies the code and will make the transition
to AttributionSource more manageable.

Bug: 190657833
Test: atest CtsCameraTestCases, Camera1 + Camera2 app
Flag: EXEMPT Strict mechanical refactor
Change-Id: I84468e14196f6a9017fe12cff78b940f2067b765