ssh key not accepted when there is "admin"

**Describe the bug**
When adding an ssh key I got this:


**Git version**
irrelevant, this is on the web interface

**Operating system**
irrelevant, this is on the web interface

**Database**
irrelevant, this is on the web interface

**To Reproduce**
Steps to reproduce the behavior:
1. Go to https://gin.g-node.org/user/settings/ssh
2. Click on add keys
3. Scroll down to section to add keys
4. copy-paste "ssh-rsa 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 admin@Mac-AC04.local" then click on add key
5. See error
6. change admin to not-admin
7. now you'll be able to add the key

**Can you reproduce the bug at https://try.gogs.io?**
no, i don't have an account

**Additional context**
Google Chrome
Version 91.0.4472.101 (Official Build) (x86_64)