migrations: Fix unused import error.

analytics/migrations/0015_clear_duplicate_counts.py

@@ -2,7 +2,7 @@
 from django.db import migrations
 from django.db.backends.postgresql_psycopg2.schema import DatabaseSchemaEditor
 from django.db.migrations.state import StateApps
-from django.db.models import Count, Sum, Q
+from django.db.models import Count, Sum
 
 def clear_duplicate_counts(apps: StateApps, schema_editor: DatabaseSchemaEditor) -> None:
     """This is a preparatory migration for our Analytics tables.