Add stats loading indicator

[nbradbury]

A user reported this issue:

Good morning. I have a problem with jetpack incorrectly reading stats. There seems to be a problem with the stats of a particular article published on 27th November 2024 around 11pm (GMT+1). It just shows I had two views when entering jetpack stats, but on Jetpack front page it was showing around 92 views at around 11.51pm (GMT+1).

In case it's not clear, the stats card on My Site was showing 92 views, but when they clicked to view stats details it only showed two views.

On Slack we wondered if the problem was that the stats details hadn't refreshed so it was showing old data. We should consider showing a loading indicator when stats are refreshing to make it more clear that current data isn't being shown.

[dangermattic]

Thanks for reporting! 👍