Use gt-relative class instead of the ambiguous gt-pr class (#23008)

`.gt-relative` is also `position: relative !important;`

There are `gt-pr-?` styles below (line 140) for `padding-right`, which
makes `.gt-pr` ambiguous

Co-authored-by: delvh <leon@kske.dev>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/repo/commit_page.tmpl

@@ -17,7 +17,7 @@
 				{{$class = (printf "%s%s" $class " isWarning")}}
 			{{end}}
 		{{end}}
-		<div class="ui top attached header clearing segment gt-pr commit-header {{$class}}">
+		<div class="ui top attached header clearing segment gt-relative commit-header {{$class}}">
 			<div class="gt-df gt-mb-4 gt-fw">
 				<h3 class="gt-mb-0 gt-f1"><span class="commit-summary" title="{{.Commit.Summary}}">{{RenderCommitMessage $.Context .Commit.Message $.RepoLink $.Repository.ComposeMetas}}</span>{{template "repo/commit_statuses" dict "Status" .CommitStatus "Statuses" .CommitStatuses  "root" $}}</h3>
 				{{if not $.PageIsWiki}}

web_src/less/helpers.less

@@ -2,7 +2,6 @@
 .gt-di { display: inline !important; }
 .gt-dif { display: inline-flex !important; }
 .gt-dib { display: inline-block !important; }
-.gt-pr { position: relative !important; }
 .gt-ac { align-items: center !important; }
 .gt-tc { text-align: center !important; }
 .gt-tl { text-align: left !important; }