Hierarchy widget: need to refresh issue to create a work item after turning on confidentiality

Summary

Doesn't look like we're updating Apollo Cache on the sidebar, or we're using a different cache for hierarchy, but we're not passing an updated parent confidentiality when creating a task.

Steps to reproduce

With :work_items_hierarchy on, create a public issue.
Make it confidential
Click "Add a task" from the hierarchy widget.
Add a title, click "Create task"

Example Project

What is the current bug behavior?

What is the expected correct behavior?

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)