Project wiki cannot be re-enabled

Summary

Once the wiki of a project has been disabled it cannot be re-enabled through the UI without receiving a Something has gone wrong on our end error.

Steps to reproduce

1. Create a project on GitLab.com.
2. Disable the wiki on that project.
3. Attempt to re-enable the wiki.
4. Observe error message.

Example Project

gitlab-gold/wiki-test

What is the current bug behavior?

The wiki of a project is not able to be re-enabled after being disabled.

What is the expected correct behavior?

The wiki of a project should be able to be disabled and then re-enabled without error.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com: 13.4.0-pre d20e5bc90ef

Workaround

Enabling the Wiki via the Projects API still works:

curl --request PUT \
  --url 'https://gitlab.com/api/v4/projects/PROJECT_ID?wiki_enabled=yes' \
  --header 'authorization: Bearer TOKEN'

ZD: https://gitlab.zendesk.com/agent/tickets/170197 (GitLab Internal)