fix: reset sender name and rate limit on toggle custom smtp off

studio/pages/project/[ref]/auth/settings.tsx

@@ -220,6 +220,8 @@ const Settings = () => {
                       SMTP_PORT: "",
                       SMTP_USER: "",
                       SMTP_PASS: "",
+                      SMTP_SENDER_NAME: "",
+                      RATE_LIMIT_EMAIL_SENT: 30,
                     })
                   }
                   setCustomSMTP(!isCustomSMTPEnabled)