Add new IncidentManager.requestAuthorization method that takes an executor.

This is @hide for Q now that we're past API freeze, and will be
@SystemApi in master.

Bug: 126700920
Bug: 126701153
Bug: 130351719
Test: bit GtsIncidentConfirmationTestCases
Test: bit GtsIncidentManagerTestCases
Change-Id: Iac6a058017a86c1927502c529e5a7f3881eb56a7