Unable to add an existing issue to a vulnerability

Summary

When trying to add an existing issue to a vulnerability, there is a UI issue which prevents most of the interactions with the input field responsible for capturing the link to the issue.

Steps to reproduce

  1. Navigate to a vulnerability: https://gitlab.com/gitlab-examples/security/security-reports/-/security/vulnerabilities/77167618
  2. Within the "Related Issues" card click on the "Add existing issue" button
  3. Try interacting (typing, pasting, deleting, etc.) with the input field that was revealed
  4. Try adding an issue link

Example Project

https://gitlab.com/gitlab-examples/security/security-reports

What is the current bug behavior?

It does not allow an existing issue to be linked

What is the expected correct behavior?

One should be able to add a URL to the input field and successfully add an issue

Relevant logs and/or screenshots

Screen_Recording_2024-09-04_at_8.38.29_PM

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

The issue is likely to have been introduced with this MR: !161791 (merged)