Add muted class to author name in repo commit list (#29989)

Before:

![image](https://github.com/go-gitea/gitea/assets/18380374/f6b3728c-ed9a-4e47-8755-89373235dff2)

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/272c85e3-620d-4758-ae4d-ad90b54e142c)

If repo is a mirror, external user's name will be white, but if user is
existed, then you will see blue names and white names together:

![image](https://github.com/go-gitea/gitea/assets/18380374/747622da-56e3-4162-b391-919787a8cee4)

---------

Co-authored-by: silverwind <me@silverwind.io>

templates/repo/commits_list.tmpl

@@ -13,16 +13,16 @@
 				{{$commitRepoLink := $.RepoLink}}{{if $.CommitRepoLink}}{{$commitRepoLink = $.CommitRepoLink}}{{end}}
 				{{range .Commits}}
 					<tr>
-						<td class="author">
+						<td class="author tw-flex">
 							{{$userName := .Author.Name}}
 							{{if .User}}
 								{{if .User.FullName}}
 									{{$userName = .User.FullName}}
 								{{end}}
-								{{ctx.AvatarUtils.Avatar .User 28 "tw-mr-1"}}<a href="{{.User.HomeLink}}">{{$userName}}</a>
+								{{ctx.AvatarUtils.Avatar .User 28 "tw-mr-2"}}<a class="muted author-wrapper" href="{{.User.HomeLink}}">{{$userName}}</a>
 							{{else}}
-								{{ctx.AvatarUtils.AvatarByEmail .Author.Email .Author.Name 28 "tw-mr-1"}}
-								{{$userName}}
+								{{ctx.AvatarUtils.AvatarByEmail .Author.Email .Author.Name 28 "tw-mr-2"}}
+								<span class="author-wrapper">{{$userName}}</span>
 							{{end}}
 						</td>
 						<td class="sha">

web_src/css/repo.css

@@ -2438,6 +2438,7 @@ tbody.commit-list {
 
 .author-wrapper {
   max-width: 180px;
+  align-self: center;
 }
 
 /* in the commit list, messages can wrap so we can use inline */