DENG-17 Removing schedules history FK to auth_user so it can be ghost migrated...

DENG-17 Removing schedules history FK to auth_user so it can be ghost migrated alongside schedules since they are tied to the same model. (#23349)

openedx/core/djangoapps/schedules/migrations/0014_historicalschedule_drop_fk.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.28 on 2020-03-09 17:02
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('schedules', '0013_historicalschedule'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='HistoricalSchedule',
+            name='history_user',
+            field=models.ForeignKey(db_constraint=False, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL),
+        ),
+    ]