feat: Introduce client management and integration updates

- Added client_id field to StoreTenantRequest and UpdateTenantRequest for tenant management.
- Updated TenantResource to include client_id in the response.
- Created migration to establish clients table and link tenants to clients.
- Migrated existing tenant integrations to client_integrations table.
- Grouped specific tenants under a shared client (OnTicket) in a new migration.
- Updated seeders to reflect new client structure and relationships.
- Adjusted integration configurations to require client instead of tenant.
- Added tests for client integration functionality and ensured existing tests reflect the new client structure.

tests/Feature/Notification/NotificationMailServiceTest.php

@@ -35,7 +35,7 @@ class NotificationMailServiceTest extends TestCase
             'integration_code' => 'email',
             'name' => 'Email',
             'url' => null,
-            'requires_tenant_configuration' => false,
+            'requires_client_configuration' => false,
             'integration_data_schema' => [],
         ]);
         $header = Attachment::query()->create([