Remove obsolete tests and unused imports in organization members and management components

- Deleted `OrganizationMembersPage` tests as they are no longer relevant.
- Removed unused `updated_at` property from test data in multiple components.
- Cleaned up redundant `useAuth` imports from `OrganizationMembersContent` and `OrganizationManagementContent`.

frontend/tests/components/admin/organizations/OrganizationActionMenu.test.tsx

@@ -35,7 +35,6 @@ describe('OrganizationActionMenu', () => {
     description: 'Leading provider',
     is_active: true,
     created_at: '2025-01-01T00:00:00Z',
-    updated_at: '2025-01-01T00:00:00Z',
     member_count: 10,
   };