fix(actions): keep workflow run trailing on one row with long branch names (#38382) (#38403)

Backport #38382 by @bircni

The flex-list refactor (#37505) raised the shared `.item-trailing`
selector's specificity, so its `flex-wrap: wrap` started overriding the
run list's intended `flex-wrap: nowrap` — a long branch name pushed the
trailing content past its fixed 280px width and wrapped the kebab menu
onto its own line.

Co-authored-by: bircni <bircni@icloud.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/actions/runs_list.tmpl

@@ -38,7 +38,7 @@
 					{{end}}
 				</div>
 			</div>
-			<div class="item-trailing">
+			<div class="run-list-item-trailing">
 				{{if $run.IsRefDeleted}}
 					<span class="ui label run-list-ref gt-ellipsis tw-line-through" data-tooltip-content="{{$run.RefTooltip}}">{{$run.PrettyRef}}</span>
 				{{else}}