Fix bulk_assign tests to not depend on removed member mutation (#2064)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mrobers1982

libs/labelbox/tests/integration/test_bulk_assign.py

@@ -1,11 +1,9 @@
 from labelbox.schema.task_assignment_status import TaskAssignmentStatus
 
 
-def test_bulk_assign_data_rows(
-    configured_batch_project_with_label, project_based_user
-):
+def test_bulk_assign_data_rows(configured_batch_project_with_label, client):
     project, _, data_row, _ = configured_batch_project_with_label
-    user = project_based_user
+    user = client.get_user()
 
     result = project.bulk_assign_data_rows(
         user_id=user.uid,
@@ -15,10 +13,10 @@ def test_bulk_assign_data_rows(
 
 
 def test_bulk_assign_data_rows_with_allowed_statuses(
-    configured_batch_project_with_label, project_based_user
+    configured_batch_project_with_label, client
 ):
     project, _, data_row, _ = configured_batch_project_with_label
-    user = project_based_user
+    user = client.get_user()
 
     result = project.bulk_assign_data_rows(
         user_id=user.uid,