temp: fix EncodeError for username in expire_and_create_entitlements (#32564)

On running the management command, we get the folowing error:

    kombu.exceptions.EncodeError: Object of type User is not JSON serializable

Pass a string of the username instead in the parameters of the tasks
created by the expire_and_create_entitlements management command.

common/djangoapps/entitlements/management/commands/expire_and_create_entitlements.py

@@ -9,15 +9,12 @@ from math import ceil
 from textwrap import dedent
 
 from django.core.management import BaseCommand
-from django.contrib.auth import get_user_model
 
 from common.djangoapps.entitlements.tasks import expire_and_create_entitlements
 from common.djangoapps.entitlements.models import CourseEntitlement
 
 logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
 
-User = get_user_model()
-
 
 class Command(BaseCommand):
     """
@@ -69,7 +66,7 @@ class Command(BaseCommand):
 
         logger.info('Looking for entitlements which may be expirable.')
 
-        support_user = User.objects.get(username=options.get('username'))
+        support_username = options.get('username')
         current_date = date.today()
         exceptional_courses = options.get('exceptional_course_uuids')
 
@@ -105,6 +102,6 @@ class Command(BaseCommand):
             start = batch_num * batch_size
             end = min(start + batch_size, entitlements_to_expire, entitlements_count)
             entitlement_ids = [entitlement.id for entitlement in entitlements[start:end]]
-            expire_and_create_entitlements.delay(entitlement_ids, support_user)
+            expire_and_create_entitlements.delay(entitlement_ids, support_username)
 
         logger.info('Done. Successfully enqueued %d tasks.', num_batches)

common/djangoapps/entitlements/tasks.py

@@ -4,6 +4,7 @@ This file contains celery tasks for entitlements-related functionality.
 from celery import shared_task
 from celery.utils.log import get_task_logger
 from django.conf import settings  # lint-amnesty, pylint: disable=unused-import
+from django.contrib.auth import get_user_model
 from edx_django_utils.monitoring import set_code_owner_attribute
 
 from common.djangoapps.entitlements.models import CourseEntitlement, CourseEntitlementSupportDetail
@@ -16,6 +17,8 @@ LOGGER = get_task_logger(__name__)
 # unwanted behavior: infinite retries.
 MAX_RETRIES = 11
 
+User = get_user_model()
+
 
 @shared_task(bind=True, ignore_result=True)
 @set_code_owner_attribute
@@ -64,7 +67,7 @@ def expire_old_entitlements(self, start, end, logid='...'):
 
 @shared_task(bind=True, ignore_result=True)
 @set_code_owner_attribute
-def expire_and_create_entitlements(self, entitlement_ids, support_user):
+def expire_and_create_entitlements(self, entitlement_ids, support_username):
     """
     Expire entitlements older than one year.
 
@@ -76,13 +79,15 @@ def expire_and_create_entitlements(self, entitlement_ids, support_user):
 
     Args:
         entitlement_ids (List<int>): A list of entitlement ids to expire.
-        support_user (django.contrib.auth.models.user): The username to attribute
-        the entitlement expiration and recreation to.
+        support_username (str): The username to attribute the entitlement
+            expiration and recreation to.
 
     Returns:
         None
 
     """
+    support_user = User.objects.get(username=support_username)
+
     first_entitlement_id = entitlement_ids[0]
     last_entitlement_id = entitlement_ids[-1]