Depends on #9178

Motivation and context

Test coverage for merging feature in consensus jobs (#8953)
Commits were cherry-picked from #9190

How has this been tested?

Case 1: check new merge buttons exist and are visible.

New freshly created jobs have status 'new'. Trying to merge new jobs should result in error notifications and a HTTP 400 status code. All notifications are closed before the next testcase

Case 2: Check consensus management page

Consensus management page has settings for consensus quorum and minimum annotation overlap. Check that the page has fields for both options. If a field is filled incorrectly the form turns red and a message appears under the form. Trying to save options with erroneous forms should do nothing - no requests are sent, no errors shown.

Case 3: Create annotations and check that job replicas merge correctly

Create annotations with one rectangle in job replicas. The rectangle is moved with a step in each job's first frame. This means that after merging, the consensus job will have a rectangle which has to fully match a rectangle inside the replica in the middle.

• Create annotations.
• Merge consensus jobs. No errors should appear. A notification message validates the merge, close it
• Go inside consensus job, remember the rectangle's positions
• Go back to the task page using browser's 'Back' button
• After loading the task page, consensus job's status should read competed
• Open the middle job replica. Rectangle should be identical to the previous one

Checklist

• I submit my changes into the develop branch
• I have created a changelog fragment
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.