Fix some broken unit tests

* Output the account username instead of the display name in an error message
that causes the tests to fail because the account has no connection.
* Move all `g_assert_no_error` checks **BEFORE** we check the any other results
that we're checking. If we're not supposed to get an error and we have one,
that error helps us find the issue which therefore makes unit test failures
actionable instead of a message to debug.

Testing Done:
Compiled and made sure the tests pass.

Reviewed at https://reviews.imfreedom.org/r/326/