Work items - Checklists in comments can't be checked

Summary

Checklist items in a work item comment can't be checked.

Steps to reproduce

1. Turn on new look
2. Write a comment that includes checkboxes like - [ ] my checkbox
3. Try to click it.
4. See nothing happens
5. Turn off new look
6. Boxes check and uncheck as expected

Example Project

gitlab (w/ work_items_view_preferences enabled and on)

What is the current bug behavior?

Nothing happens

What is the expected correct behavior?

Checklist toggles state

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

(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\`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(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)

Possible fixes