Fix `import_github_repo_spec.rb` test

This is a follow up of this and subsequent comments: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22458#note_127068101

The import_github_repo_spec.rb spec has not been running on any pipelines since it is tagged :orchestrated and there is no test scenario for it in the gitlab-qa project. Remove the :orchestrated tag.

Furthermore, the test is broken and the following three issues need to be addressed:

1. ProjectImportedFromGithub class imports from the Project class which fabricates the project via api and so the fabricate! method of ProjectImportedFromGithub is not used.

2. The test proceeds before waiting for the "Done" status on /import/github/status page:

Import in-progress:

:

Done:

3. Any updates to UI as indicated in this comment needs to be addressed: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22458#note_127068101