Added space between avatar and username (#21825)

Added space between avatar and username which is missing on verified
commit message and avatar is too close to username which is don't look
nice.

Current state

![image](https://user-images.githubusercontent.com/3164256/202007728-d7d6ecac-f754-454c-a67f-e422f4aac5a5.png)


This is how it looks after change

![image](https://user-images.githubusercontent.com/3164256/202007984-d4a38a1c-7c24-4278-aa0f-9aa51c10f772.png)

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/repo/commit_page.tmpl

@@ -200,7 +200,7 @@
 							{{else}}
 								<span class="ui text mr-3">{{.locale.Tr "repo.commits.signed_by_untrusted_user_unmatched"}}:</span>
 							{{end}}
-							{{avatar .Verification.SigningUser 28}}
+							{{avatar .Verification.SigningUser 28 "mr-3"}}
 							<a href="{{.Verification.SigningUser.HomeLink}}"><strong>{{.Verification.SigningUser.GetDisplayName}}</strong></a>
 						{{else}}
 							<span title="{{.locale.Tr "gpg.default_key"}}">{{svg "gitea-lock-cog" 16 "mr-3"}}</span>