Fix revert commit query

What does this MR do?

We use the same query handler for cherry-pick and revert features.

In !55970 (diffs) we updated the query handler for retrieving branches and defaulted to an empty array if no data.Branches object is present.

This MR ensures the response from the backend can also be an array when reverting a commit.

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.

Availability and Testing

• Tested in all supported browsers

Related to #327064