feat(organization)!: simplify organization detection for retrieving u…

…sage metrics (#5332)

### 📣 Summary
Simplified the logic for detecting the organization when retrieving
project usage, storage, and NLP minutes.
Improved code readability and maintainability.


### 📖 Description
This PR refactors the organization detection logic used to retrieve
metrics such as project usage, storage, and NLP minutes. The simplified
makes the code easier to read and maintain.

The detection is now based on whether the organization is a Multi-Member
Organization (MMO). Additionally, it assumes that all projects belong
directly to the organization rather than its individual members.

kobo/apps/organizations/views.py

@@ -1,11 +1,4 @@
-from django.db.models import (
-    QuerySet,
-    Case,
-    When,
-    Value,
-    CharField,
-    OuterRef,
-)
+from django.db.models import Case, CharField, OuterRef, QuerySet, Value, When
 from django.db.models.expressions import Exists
 from django.utils.http import http_date
 from rest_framework import viewsets
@@ -102,7 +95,9 @@ def assets(self, request: Request, *args, **kwargs):
         ### Additional Information
         For more details, please refer to `/api/v2/assets/`.
         """
-        organization = self.get_object()  # Call check permissions
+
+        # `get_object()` checks permissions
+        organization = self.get_object()
 
         # Permissions check is done by `OrganizationAssetViewSet` permission classes
         asset_view = OrganizationAssetViewSet.as_view({'get': 'list'})
@@ -154,8 +149,8 @@ def service_usage(self, request, pk=None, *args, **kwargs):
         >       }
         ### CURRENT ENDPOINT
         """
-        self.get_object()  # check permissions
 
+        self.get_object()  # This call is necessary to check permissions
         serializer = ServiceUsageSerializer(
             get_database_user(request.user),
             context=self.get_serializer_context(),
@@ -210,6 +205,7 @@ def asset_usage(self, request, pk=None, *args, **kwargs):
         ### CURRENT ENDPOINT
         """
 
+        # `get_object()` checks permissions
         organization = self.get_object()
 
         user_id = get_database_user(request.user).pk