mod_http_muc_log: Fix error in js when displaying presence is disabled When the form is hidden, attempting to index forms[0] throws an error, however this is harmless since the script is finished by that point.

<tr>
  <td colspan="2">
    <script src="https://hcaptcha.com/1/api.js" async defer></script>
    <div class="h-captcha" data-sitekey="{captcha_public_key}"></div>
  </td>
</tr>