realms: Create default system user groups for internal realm.

Since we include internal realms while creating system groups
in "0382_create_role_based_system_groups.py", we should do it
when creating new internal realms as well to be consistent.

Tests are changed accordingly as UserGroup objects are created.
We also change the user group ids used in api docs examples
such that user groups are of correct realm.

zerver/lib/server_initialization.py

@@ -3,6 +3,7 @@ from typing import Iterable, Optional, Tuple
 from django.conf import settings
 
 from zerver.lib.bulk_create import bulk_create_users
+from zerver.lib.user_groups import create_system_user_groups_for_realm
 from zerver.models import (
     Realm,
     RealmAuditLog,
@@ -25,6 +26,7 @@ def create_internal_realm() -> None:
         realm=realm, event_type=RealmAuditLog.REALM_CREATED, event_time=realm.date_created
     )
     RealmUserDefault.objects.create(realm=realm)
+    create_system_user_groups_for_realm(realm)
 
     # Create some client objects for common requests.  Not required;
     # just ensures these get low IDs in production, and in development

zerver/openapi/zulip.yaml

@@ -14303,7 +14303,7 @@ paths:
                 type: array
                 items:
                   type: integer
-              example: [1, 2]
+              example: [8, 9]
           required: false
       responses:
         "200":
@@ -16459,7 +16459,7 @@ components:
         The ID of the target user group.
       schema:
         type: integer
-      example: 22
+      example: 29
       required: true
     QueueId:
       name: queue_id

zerver/tests/test_user_groups.py

@@ -39,7 +39,7 @@ class UserGroupTestCase(ZulipTestCase):
 
     def test_user_groups_in_realm_serialized(self) -> None:
         realm = get_realm("zulip")
-        user_group = UserGroup.objects.first()
+        user_group = UserGroup.objects.filter(realm=realm).first()
         assert user_group is not None
         membership = UserGroupMembership.objects.filter(user_group=user_group).values_list(
             "user_profile_id", flat=True