Submit Review does nothing; browser JS console indicates 500 error at drafts_service.js:23
<!--IssueSummary start-->
<details>
<summary>
Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards.
</summary>
- [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=510123)
</details>
<!--IssueSummary end-->
### Summary
I have been putting some review notes together on an MR and when I go to submit them I get a 500 error.
### Steps to reproduce
I don't know - 500 error is your error and I expect you will have server-side logs of it that allow you to reproduce. I am literally going to have to copy and paste my MR feedback into an email or something because I cannot send it to my colleague through GitLab.
### What is the current *bug* behavior?
I put some review comments on an MR, I press the "Finish Review" button, I press the "Submit Review" button in the dialog. Nothing happens and the dialog does not go away. When I open Chrome developer tools and go to the js console to reproduce it, it's clear that it's a 500 error. See below.
### What is the expected *correct* behavior?
My review comments are submitted successfully and the server reponds with a 200, i guess
### Relevant logs and/or screenshots
From the Chrome dev console upon clicking "Submit Review":
```
drafts_service.js:23
POST https://gitlab.com/[redacted]/-/merge_requests/133/drafts/publish 500 (Internal Server Error)
(anonymous) @ browserapierrors.js:148
apply @ xhr.js:142
(anonymous) @ xhr.js:210
JgJM.e.exports @ xhr.js:15
Iu5f.e.exports @ dispatchRequest.js:56
Promise.then
SKMx.l.request @ Axios.js:88
SKMx.r.forEach.l.<computed> @ Axios.js:140
(anonymous) @ bind.js:9
publish @ drafts_service.js:23
j @ actions.js:88
(anonymous) @ vuex.esm.js:851
d.dispatch @ vuex.esm.js:516
dispatch @ vuex.esm.js:406
i.dispatch @ vuex.esm.js:779
E.forEach.n.<computed> @ vuex.esm.js:1064
submitReview @ submit_dropdown.vue:154
submit @ submit_dropdown.vue:1
mn @ vue.runtime.esm.js:3033
n @ vue.runtime.esm.js:1832
Qi.o._wrapper @ vue.runtime.esm.js:7500
n @ helpers.js:93
```
### Output of checks
<!--If you are reporting a bug on GitLab.com, uncomment below-->
This bug happens on GitLab.com
<!--and uncomment below if you have /label privileges-->
<!--/label ~"reproduced on GitLab.com"-->
<!--or follow up with an issue comment of `@gitlab-bot label ~"reproduced on GitLab.com"` if you do not-->
#### Results of GitLab environment info
<!--Input any relevant GitLab environment information if needed.-->
<details>
<summary>Expand for output related to GitLab environment info</summary>
<pre>
(For installations with omnibus-gitlab package run and paste the output of: \`sudo gitlab-rake gitlab:env:info\`) (For installations from source run and paste the output of: \`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production\`)
</pre>
</details>
#### Results of GitLab application Check
<!--Input any relevant GitLab application check information if needed.-->
<details>
<summary>Expand for output related to the GitLab application check</summary>
<pre>
(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:check SANITIZE=true`)
(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true`)
(we will only investigate if the tests are passing)
</pre>
</details>
### Possible fixes
<!--If you can, link to the line of code that might be responsible for the problem.-->
<!--If you don't have /label privileges, follow up with an issue comment of `@gitlab-bot label ~"type::bug"`-->
issue