Refactor verify runner tests to table tests and better assertions

What does this MR do?

Refactor some of the GitLab client tests to table tests.

Why was this MR needed?

Tests are also code that we maintain. Refactoring tests to table tests helps with maintenance. Also, running table tests in parallel will help reduce the time it takes to run tests.

What's the best way to test this MR?

go test -race ./network/...