Ignore additional state changes after expecations have been met (#833)
Ignore additional state changes after expecations have been met (#833)

Motivation:

The `RecordingConnectivityDelegate` calls XCTFail when it receives a
state change notification when no expecations are set. This can cause
failures in scenarious where we don't care about additional state
changes.

Modifications:

- Ignore state changes when there's no verification callback set.

Result:

Less flaky tests
grpc/grpc-swift,grpc/grpc-swift,grpc/grpc-swift,grpc/grpc-swift,grpc/grpc-swift