corporate: Rename CustomerPlan.invoice_overdue_email_sent field.

Renames invoice_overdue_email_sent to stale_audit_log_data_email_sent
to better reflect the email and state that field is tracking for
the CustomerPlan.

corporate/migrations/0046_rename_customerplan_invoice_overdue_email_sent.py

@@ -0,0 +1,17 @@
+# Generated by Django 5.1.8 on 2025-05-27 14:26
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("corporate", "0045_zulipsponsorshiprequest_plan_to_use_zulip"),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name="customerplan",
+            old_name="invoice_overdue_email_sent",
+            new_name="stale_audit_log_data_email_sent",
+        ),
+    ]