Stop Vote/endorsement button links being crawled by Google

We're seeing a large number of low-value URLs being crawled by Googlebot, which is polluting our Google Search Console reports.

The links are generated by the vote/endorsement button.

Because this anchor has a real href, Googlebot follows it and indexes one prompt_login URL per idea, none of which have any SEO or user value.

Please add rel="nofollow" to the vote/endorsement button links (the prompt_login anchor) so that search engines no longer follow and crawl them. This is the cleanest fix on the template side and would immediately stop these URLs from being discovered.