Swap order of usage and team members for org users

Org users, when looking at the page for their org, see:
> Usage
> Team members

When they click into a service it switches to:
> Team members
> Usage

This is jarring. It should stay consistent. I think it that _Usage_ then
_Team members_ is the natural way of ordering the navigation at the
organisation level, so let’s follow that through to the service level.

This does mean that if someone is a member of both an organisation and a
service that the nav will jump (because it’ll switch to the existing,
service-level order of _Team members_ then _Usage_) but it’s going to
jump anyway because you get all the extra navigation items when you’re a
member of a service.

app/templates/main_nav.html

@@ -29,8 +29,8 @@
       <li><a href="{{ url_for('.api_integration', service_id=current_service.id) }}" {{ main_navigation.is_selected('api-integration') }}>API integration</a></li>
     {% endif %}
   {% elif current_user.has_permissions(allow_org_user=True) %}
-    <li><a href="{{ url_for('.manage_users', service_id=current_service.id) }}" {{ main_navigation.is_selected('team-members') }}>Team members</a></li>
     <li><a href="{{ url_for('.usage', service_id=current_service.id) }}" {{ main_navigation.is_selected('usage') }}>Usage</a></li>
+    <li><a href="{{ url_for('.manage_users', service_id=current_service.id) }}" {{ main_navigation.is_selected('team-members') }}>Team members</a></li>
   {% endif %}
   </ul>
 </nav>

tests/app/main/test_permissions.py

@@ -373,8 +373,8 @@ def test_service_navigation_for_org_user(
     assert [
         item.text.strip() for item in page.select('nav.navigation a')
     ] == [
-        'Team members',
         'Usage',
+        'Team members',
     ]