Fix display member unit in the menu bar if there are no hidden members in public org (#27795)

Follow #26363.
I missed that org templates also using
`templates/user/overview/header.tmpl`.
You can confirm this problem in https://gitea.com/gitea/-/projects with
anonymous access.

Before: (no login)

![image](https://github.com/go-gitea/gitea/assets/18380374/e285565c-ca65-4b18-9ff7-434c6367c13a)

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/81e7532a-c458-4552-8d75-6896538e42cb)

templates/user/overview/header.tmpl

@@ -27,14 +27,14 @@
 	{{end}}
 
 	{{if .ContextUser.IsOrganization}}
-		{{if .IsOrganizationMember}}
-			<a class="item" href="{{$.OrgLink}}/members">
+		{{if .NumMembers}}
+			<a class="{{if $.PageIsOrgMembers}}active {{end}}item" href="{{$.OrgLink}}/members">
 				{{svg "octicon-person"}}&nbsp;{{ctx.Locale.Tr "org.members"}}
-				{{if .NumMembers}}
-					<div class="ui small label">{{.NumMembers}}</div>
-				{{end}}
+				<div class="ui small label">{{.NumMembers}}</div>
 			</a>
-			<a class="item" href="{{$.OrgLink}}/teams">
+		{{end}}
+		{{if .IsOrganizationMember}}
+			<a class="{{if $.PageIsOrgTeams}}active {{end}}item" href="{{$.OrgLink}}/teams">
 				{{svg "octicon-people"}}&nbsp;{{ctx.Locale.Tr "org.teams"}}
 				{{if .NumTeams}}
 					<div class="ui small label">{{.NumTeams}}</div>