"\r\n" is a line break in windows. Since blank space is ignored by html, it won't add anything when viewing in html emails, but adds a blank line (or sometimes two on Linux servers) in the code.
If you sent a plain text email with no html content, you would have seen the breaks caused by "\r\n".
To have less space, remove one or all of the lines:
$MailBody = $MailBody . "<br>";
They each represent a line and you have four of them between each field. You could probably remove the two at the top and just leave the two at the bottom.