There are many instances in the gRPC unit tests where ASSERT_OK is used with StatusWith<T> objects. While this functionally works to assert that these are in fact OK, the exception that is thrown when the assertion fails does not print useful information about the error that was experienced. We should update the gRPC unit tests to invoke .getStatus() when asserting on StatusWith objects so that future BFs are more easily diagnose-able.

See BF-29927 for examples of poor log messages.