Do not list links without anchor description in DownloadPageAPI

[ewilly]

Some webpages could have HREF in an anchor without description (<a href="url">description</a>) which lead in key with None value in the get_web_page_links list and result in erro in the autoupdate_app_sources.py script

[fflorent]

No regression detected on my side.

I guess links with no description are not meant to be scrapped. That's arguable, we might want to just return links (href), but let's see in a future work(?)

At least, that patch does not prevent the autoupdate of Piwigo, if that makes the autoupdate work for Grafana, I am in favor.

[Salamandar]

I don't get what you mean by "HREF in an anchor without description". Can you give me an example ?

[ewilly]

For example in that page https://grafana.com/grafana/download?edition=oss there is <a href=https://twitter.com/grafana target=_blank rel=noopener aria-label="Grafana Labs on X"><i class="fa fa-twitter"></i></a>
so an anchor with an href without description <a href="url"></a> instead of <a href="url">description</a>.