Plugin Directory: Invalid subdomain links in translations list

[SergeyBiryukov]

Background: ​Slack thread.

​https://wordpress.org/plugins/pods/ links to ​https://pt-br.wordpress.org/plugins/pods/, which does not exist.

The correct link for Brazilian Portuguese would have been ​https://br.wordpress.org/plugins/pods/.

The locale cannot generally be used as subdomain, it needs to pull the associated subdomain from the locales table.

[SergeyBiryukov]

The theme already pulls the list of locale sites in hreflang_link_attributes().

2690.patch​ moves that code to the plugin and reuses it in the translations section.

[ocean90]

Thanks for the patch. There's actually a new table which we'll use for that.

[ocean90]

In 5371:

Plugin Directory: Fix invalid subdomain links in translations list.

Our subdomains are not the same as locale slugs. To get the correct domains query the sites by WordPress locale.

See [5348].
Fixes #2690.