Edit file actions not available for Branches with NON-ASCII characters

Summary

It is currently not possible to edit a file in the online editor that is on a branch with a non ascii name.

Steps to reproduce

• Take a project
• Create a new branch with a name like "Ä"
• Try to edit a file. Edit Button, which is usally there, does not appear.

Example Project

Example Project with example Branch: https://gitlab.com/think/gitlab-branch-test/blob/%C3%84hh/README.md Try to edit this file. Edit Button is not available.

If switch back to master, edit is totally fine. https://gitlab.com/think/gitlab-branch-test/blob/master/README.md

What is the current bug behavior?

WebIDE is not available. So cannot edit files just using the online editor.

What is the expected correct behavior?

Online editing in the online editor should be possible. Edit Button should be available.

Relevant logs and/or screenshots

Shows the missing edit button for a branch with a non ascii character.

Output of checks

This bug happens on GitLab.com