twitter: embedded timeline broken unless logged in

[GraemeWatt]

The HEPData homepage shows a feed from the @HEPData X (Twitter) account:

https://github.com/HEPData/hepdata/blob/b1175116a19774584e0e2d18daf92bd534a4c800/hepdata/modules/theme/templates/hepdata_theme/home.html#L161-L165

This shows "Nothing to see here - yet" unless the user is logged in to X (Twitter) from the same browser and their browser allows cross-site tracking (often not the default). This seems to be a known problem for almost a year with no definite resolution:

https://devcommunity.x.com/t/again-list-widget-says-nothing-to-see-here-yet-if-logged-out/198782

I tried a proposed third-party workaround (https://www.athabasca.dev/twitterwidget), but it did not work when testing locally. For now, I'll leave this issue open until a solution can be found. I'll add some explanatory text underneath the embedded Twitter widget:

Tweets are not displayed unless you are logged into <a href="https://X.com" target="_blank">X (Twitter)</a> and your browser settings allow cross-site tracking.

In the longer term, if no solution becomes available, we should consider removing the embedded Twitter widget from the HEPData homepage.