Class `code` breaks Usage statistics -> Preview Payload functionality

Summary

Currently Preview Payload button doesn't work. It doesn't show payload when it received from the server

It's quite likely caused by recent changes to .code class applied to the element. If I remove .code class, the element works.

https://gitlab.com/gitlab-org/gitlab/blob/59a43d0b5dabdeab70685c4ad3d76c3b24ff5769/app/views/admin/application_settings/_usage.html.haml#L32-32

Also, if I rename tag from pre to, for example p it works as well.

Steps to reproduce

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)

Possible fixes