ICalUtil::getUserIdByEmail

static function getUserIdByEmail(array $userInfo): ?string
{
	$parameters = [
		'filter' => [
			'EMAIL' => $userInfo['EMAIL'],
		],
		'select' => ['ID',],
		'limit' => 1,
	];

	$userDd = UserTable::getList($parameters);
	if ($user = $userDd->fetch())
	{
		return $user['ID'];
	}

	return self::getExternalUserByEmail($userInfo, $errorCollection);
}