WifiScanningServiceImpl: Add ClientInfo null checks

Add missing null checks for |ClientInfo| in a few places. ClientInfo
could end up being null if there was a pending cleanup of the client
before processing of the request in the appropriate state machine.

Also, add a unit test to simulate the scenario in the bug specified.

BUG: 30241457
Change-Id: Ic4412ae03b5176764b10cba357d19086c0c09e6e
TEST: Unit tests
2 files changed
tree: b8ce217705d7e9ccdf418c7f32eb83e7ecd2adae
  1. service/
  2. tests/