INCR-263 Run python-modernize on lms/djangoapps/instructor_task/config and lms/djangoapps/instructor_task/management (#20559)

* run python modernize

* run isort

* Fix quality

lms/djangoapps/instructor_task/config/models.py

@@ -2,6 +2,8 @@
 Models for configuration of settings relevant
 to instructor tasks.
 """
+from __future__ import absolute_import
+
 from config_models.models import ConfigurationModel
 from django.db.models import IntegerField
 

lms/djangoapps/instructor_task/management/commands/fail_old_tasks.py

@@ -1,4 +1,7 @@
-from __future__ import print_function, unicode_literals
+"""
+Commands to fail old tasks
+"""
+from __future__ import absolute_import, print_function, unicode_literals
 
 from datetime import datetime
 

lms/djangoapps/instructor_task/management/commands/tests/test_fail_old_tasks.py

@@ -1,3 +1,8 @@
+"""
+Tests for failing old tasks
+"""
+from __future__ import absolute_import
+
 from datetime import datetime
 
 import ddt