fix: remove DELETE query filter (#1286)

Remove `DELETE` queries from the dangerous query filter as these are
a normal part of the Notify app's behaviour.

aws/rds/sentinel.tf

@@ -1,5 +1,5 @@
 locals {
-  postgres_dangerous_queries       = ["ALTER ", "CREATE ", "DELETE ", "DROP ", "GRANT ", "REVOKE ", "TRUNCATE "]
+  postgres_dangerous_queries       = ["ALTER ", "CREATE ", "DROP ", "GRANT ", "REVOKE ", "TRUNCATE "]
   postgres_dangerous_queries_lower = [for sql in local.postgres_dangerous_queries : lower(sql)]
 }