Fixes accessibility of empty repository commit status (#22632)

Avoid empty labelled anchor in repo without commits.

Contributed by @forgejo.

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templates/repo/commit_statuses.tmpl

@@ -1,4 +1,4 @@
-<a class="ui link commit-statuses-trigger vm"{{if eq (len .Statuses) 1}}{{$status := index .Statuses 0}}{{if $status.TargetURL}} href="{{$status.TargetURL}}"{{end}}{{end}}>{{template "repo/commit_status" .Status}}</a>
+{{if eq (len .Statuses) 1}}{{$status := index .Statuses 0}}{{if $status.TargetURL}}<a class="ui link commit-statuses-trigger vm" href="{{$status.TargetURL}}">{{template "repo/commit_status" .Status}}</a>{{end}}{{end}}
 <div class="ui commit-statuses-popup commit-statuses tippy-target">
 	<div class="ui relaxed list divided">
 		{{range .Statuses}}