Partially fix broken Geo end-to-end test

What does this MR do?

Partially fix broken test that failed on nightly execution (https://gitlab.slack.com/archives/CGLMP1G7M/p1560838084003600).

Now, in the creation of the issue resource via API, the labels attribute is required.

For more details about this MR being a partial fix see: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14265#note_184404978

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content