Remove temporarily duplicated comments when submitting an MR review

Summary

Under certain circumstances (slow network speeds?), when submitting a review in an MR, the pending comments appear temporarily duplicated before the submission is complete:

CleanShot_20210513115217

Possibly related to:

• #294015 (closed)
• #215953 (closed)

Steps to reproduce

1. Add comments to a review in an MR
2. Submit the review

What is the current bug behavior?

When submitting a review in an MR, the pending comments appear temporarily duplicated before the submission is complete.

What is the expected correct behavior?

The pending comments should not appear duplicated.

Output of checks

This bug happens on GitLab.com