feat(mailer): Log error message when sending selfservice forgotten mail fails

src/mailer.ts

@@ -111,7 +111,7 @@ export class Mailer {
             });
         } catch (error) {
             if (Mailer.testing) { return true; }
-            console.error("Error while sending selfservice forgotten mail:", error);
+            console.error("Error while sending selfservice forgotten mail:", error.message);
             throw new MailSendingError();
         }
     }