Unregister configuration listener after the WindowProcessController

was disallowed to be overridden.

If the A11y or voice interaction service start after an activity,
the WindowProcessController's configuration was overridden by the activity.
After the mIsActivityConfigOverrideAllowed changed to false, and the activity
finished, the app's application and services will never receive new configuration.

Test: WindowProcessControllerTests
Test: ProcessRecordTests

Bug: 201457378
Change-Id: I971d7ff957a39447a477525e6a4924ddfb4bfa1c