New Issues not linking to Epics when using quick actions

Summary

When creating an issue and using the /set_parent quick action the issue gets created but does not link to the epic.

Steps to reproduce

  1. Create an issue in the Dedicated issue tracker using the switchboard_tenant_model_schema_update. (Remove mentions to users if testing to reduce noise 🙏 )
  2. The issue will create, but will not link to the epic.

Example Project

What is the current bug behavior?

Epic does not link to issue

What is the expected correct behavior?

Epic should link to issue when creating

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