Report correct userId in onUserMayRequestUnlock.

obtainMessage with two arguments will set the user id as the object, but
this value is retrieved as msg.arg1. We need to call obtainMessage with
three arguments instead to make the second argument the userId. Thir
third argument will be ignored by the receiver.

Test: atest TrustTests:UserUnlockRequestTest
Bug: b/278323473
Change-Id: Ie08c643f9fb5fbbe7f107a1f267074805ddc500b