Add BluetoothPbapObexServerTest

This CL adds tests for following methods of BluetoothPbapObexServer:
- onConnect
- onDisconnect
- onAbort
- onPut
- onDelete
- onClose
- onAuthenticationFailure
- closeStream
- logHeader

Remaining ones will be handled in a different CL.

Bug: 237548430
Test: atest BluetoothPbapObexServerTest
Ignore-AOSP-First: Merging into internal branches first
    in order to resolve merge conflict
Change-Id: I8813f812f7d4125eb0bdbef5953bc96fc2e0af7b
Merged-In: I8813f812f7d4125eb0bdbef5953bc96fc2e0af7b