INCR-279 Run python-modernize on lms/djangoapps/commerce/migrations (#20580)

* run python modernize

* run isort

lms/djangoapps/commerce/migrations/0001_data__add_ecommerce_service_user.py

 # -*- coding: utf-8 -*-
+from __future__ import absolute_import
+
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.db import models, migrations
-
+from django.db import migrations, models
 
 USERNAME = settings.ECOMMERCE_SERVICE_WORKER_USERNAME
 EMAIL = USERNAME + '@fake.email'

lms/djangoapps/commerce/migrations/0002_commerceconfiguration.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
-from django.db import migrations, models
 import django.db.models.deletion
 from django.conf import settings
+from django.db import migrations, models
 
 
 class Migration(migrations.Migration):

lms/djangoapps/commerce/migrations/0003_auto_20160329_0709.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.db import migrations, models
 

lms/djangoapps/commerce/migrations/0004_auto_20160531_0950.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.db import migrations, models
 

lms/djangoapps/commerce/migrations/0005_commerceconfiguration_enable_automatic_refund_approval.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.db import migrations, models
 

lms/djangoapps/commerce/migrations/0006_auto_20170424_1734.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.db import migrations, models
 

lms/djangoapps/commerce/migrations/0007_auto_20180313_0609.py

 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.db import migrations, models