Bug 16522: (follow-up) Remove HTML links from email

Bug 16522: (follow-up) Remove HTML links from email

The emails sent for cart and list are plain text and any
<a> tag will be scrubbed by HtmlToText. So we can remove
those links.

This also solves an issue with the original patch set,
where the error below would appear on sending a cart or
list email from the staff interface:

Template process failed: file error - biblio_a_href: not found at /kohadevbox/koha/C4/Templates.pm line 127

Signed-off-by: Heather Hernandez <heather_hernandez@nps.gov>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>