Permission based on user account autocomplete not working when using Realname module

Hello,

thank you for this awesome module, I found little bug when my site used Realname module. Your widget parse usernames from string when saving form input. It's not good practise, I look into entity reference field, which is using uids EntityAutocomplete::validateEntityAutocomplete

I made quickfix which resolves my issue, I'm happy to create patch but maybe it has other consequences

/**
   * Gets the user ids which have been submitted by form.
   *
   * Users which will gain granted access to taxonomy terms.
   *
   * @return array
   *   The user ids which have been submitted.
   */
  public function getSubmittedUserIds() {
    /* There's a $this->oFormState->getValues() method, but
     * it is loosing multiple form values. Don't know why.
     * So there're some custom lines on the $_REQUEST array. */
    $sRawUsers = $_REQUEST['access']['user'];

    if (empty($sRawUsers)) {
      return [];
    }

    $aRawUsers = Tags::explode($sRawUsers);

    $aUserIds = [];
    if (!empty($aRawUsers)) {
      foreach ($aRawUsers as $sRawUser) {
        if (preg_match("/.+\s\(([^\)]+)\)/", $sRawUser, $matches)) {
          $aUserIds[] = $matches[1];
        }
      }
    }

    return $aUserIds;
  }