feat(billing): merge NLP addons feature into main TASK-1255 (#5265)

### 📣 Summary
Adds billing and tracking support for one-time addons.


### 💭 Notes
This PR is for merging the `billing-addons-backend` feature branch into
`main`. All substantive changes have already been reviewed and tested,
though further testing will be conducted on the beta server once the
merge is completed. The frontend feature has been placed behind a
feature flag, and so will require the param
`?ff_oneTimeAddonsEnabled=true`.

---------

Co-authored-by: Jessica Thomas <jessica.thomas@kobotoolbox.org>
Co-authored-by: RuthShryock <ruthieshryock@gmail.com>
Co-authored-by: Guillermo <lgar89@gmail.com>
Co-authored-by: RuthShryock <81720958+RuthShryock@users.noreply.github.com>
Co-authored-by: Olivier Léger <olivierleger@gmail.com>

hub/admin/extend_user.py

@@ -25,6 +25,7 @@
 from kobo.apps.trash_bin.models.account import AccountTrash
 from kobo.apps.trash_bin.utils import move_to_trash
 from kpi.models.asset import AssetDeploymentStatus
+
 from .filters import UserAdvancedSearchFilter
 from .mixins import AdvancedSearchMixin
 
@@ -167,9 +168,7 @@ class ExtendedUserAdmin(AdvancedSearchMixin, UserAdmin):
     actions = ['remove', 'delete']
 
     class Media:
-        css = {
-            'all': ('admin/css/inline_as_fieldset.css',)
-        }
+        css = {'all': ('admin/css/inline_as_fieldset.css',)}
 
     @admin.action(description='Remove selected users (delete everything but their username)')
     def remove(self, request, queryset, **kwargs):
@@ -293,9 +292,13 @@ def _filter_queryset_for_organization_user(self, queryset):
         """
         Displays only users whose organization has a single member.
         """
-        return queryset.annotate(
-            user_count=Count('organizations_organization__organization_users')
-        ).filter(user_count__lte=1).order_by('username')
+        return (
+            queryset.annotate(
+                user_count=Count('organizations_organization__organization_users')
+            )
+            .filter(user_count__lte=1)
+            .order_by('username')
+        )
 
     def _remove_or_delete(
         self,

jsapp/js/account/accountSidebar.tsx

@@ -48,10 +48,6 @@ function AccountSidebar() {
     setShowPlans(true);
   }, [subscriptionStore.isInitialised]);
 
-  const showAddOnsLink = useMemo(() => {
-    return !subscriptionStore.planResponse.length;
-  }, [subscriptionStore.isInitialised]);
-
   return (
     <nav className={styles.accountSidebar}>
       <AccountNavLink
@@ -78,14 +74,12 @@ function AccountSidebar() {
                 name={t('Plans')}
                 to={ACCOUNT_ROUTES.PLAN}
               />
-              {showAddOnsLink && (
-                <AccountNavLink
-                  iconName='plus'
-                  name={t('Add-ons')}
-                  to={ACCOUNT_ROUTES.ADD_ONS}
-                  isNew
-                />
-              )}
+              <AccountNavLink
+                iconName='plus'
+                name={t('Add-ons')}
+                to={ACCOUNT_ROUTES.ADD_ONS}
+                isNew
+              />
             </>
           )}
         </>