Checklist items in Epics showing the Convert to task option

Summary

The Convert to task option is showing up on checklist items in Epics. When you try to convert the checklist item, it fails (because Epics can't have tasks as children) and deletes the checklist item.

Steps to reproduce

Create an Epic
Add a checklist
Hover over a checklist item, select the three dots menu, and observe that the Convert to task option is showing up
Click the Convert to task option and observe that the checklist item is deleted and the checklist items fails to convert to task

Example Epic

https://gitlab.com/groups/gitlab-org/plan-stage/-/epics/53

What is the current bug behavior?

When you hover over a checklist item on an Epic, the Convert to task option is shown in the three dots menu.

What is the expected correct behavior?

Checklist items on Epics should not have the Convert to task option, because Epics cannot have tasks as children.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com /label reproduced on GitLab.com

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)