feat(migration): Add mod_message and notify fields to UserRegistration

Introduces 'mod_message' field for storing moderation comments and
'notify' field for enabling notification settings in the
UserRegistration model to enhance registration management.

This allows for better tracking and communication related to user
registration status and actions.

src/synapse_registration/registration/migrations/0004_userregistration_mod_message_userregistration_notify.py

@@ -0,0 +1,23 @@
+# Generated by Django 5.1.3 on 2024-11-30 15:08
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("registration", "0003_userregistration_timestamp_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="userregistration",
+            name="mod_message",
+            field=models.TextField(blank=True, default=""),
+        ),
+        migrations.AddField(
+            model_name="userregistration",
+            name="notify",
+            field=models.BooleanField(default=True),
+        ),
+    ]