Issue titles in RSS feed are double encoded (htmlentities)

Summary

Issue titles are double encoded in rss feed.

Steps to reproduce

Call issue list, create an issue with special characters in title, e. g. & or " and then click the subscribe button for the RSS feed.

Example Project

https://gitlab.com/Croydon/testproject-issues/

What is the current bug behavior?

  <title>This issue is using html &amp;amp; special &amp;quot;characters&amp;quot; that are encoded</title>

What is the expected correct behavior?

  <title>This issue is using html &amp; special &quot;characters&quot; that are encoded</title>

Relevant logs and/or screenshots

https://gitlab.com/Croydon/testproject-issues/issues.atom

Output of checks

This bug happens on GitLab.com