Download buttons show up instead of the diff when reloading the page while the "Show one file at a time on merge request's Changes tab" preference is active

Summary

Steps to reproduce

Go to https://gitlab.com/-/profile/preferences
Enable the "Show one file at a time on merge request's Changes tab" preference
Go to a MR
Select the "Changes" tab
Refresh the page

Example Project

What is the current bug behavior?

Two download buttons show up:

What is the expected correct behavior?

The diff should show up.

ℹ️ If I collapse and expand the file, the diff shows up.

Relevant logs and/or screenshots

Output of checks

This bug happens 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)