fix href on label in sidebar (#15022)

Author: noerw

templates/repo/issue/labels/labels_sidebar.tmpl

@@ -2,10 +2,10 @@
 	<span class="no-select item {{if .ctx.HasSelectedLabel}}hide{{end}}">{{.ctx.i18n.Tr "repo.issues.new.no_label"}}</span>
 	<span class="labels-list">
 		{{range .ctx.Labels}}
-			{{template "repo/issue/labels/label" dict "root" $ "label" .}}
+			{{template "repo/issue/labels/label" dict "root" $.root "label" .}}
 		{{end}}
 		{{range .ctx.OrgLabels}}
-			{{template "repo/issue/labels/label" dict "root" $ "label" .}}
+			{{template "repo/issue/labels/label" dict "root" $.root "label" .}}
 		{{end}}
 	</span>
 </div>