Enable all gitaly features in spinach tests

What does this MR do?

Enable all gitaly features in spinach tests

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

We want to catch Gitaly related errors as early as possible. We already have all Gitaly features enabled on RSpecs, so this change will allows to have all our tests work with Gitaly.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes gitaly#521 (closed)