Blog Stats Widget: add some default styling

[jeherve]

The Blog Stats Widget is functional, but should we add some default styling?

[dereksmart]

If we add custom styles to these, we'll need to be careful in overwriting css that themes may have already, and also that we don't overwrite any styles that have been customized for dotcom sites.

[lancewillett]

Similar to #5891 we should add basic general styles here.

[stale]

This issue has been marked as stale. This happened because:

• It has been inactive in the past 6 months.
• It hasn’t been labeled `[Pri] Blocker`, `[Pri] High`.

No further action is needed. But it's worth checking if this ticket has clear reproduction steps and it is still reproducible. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.

[Aurorum]

Just noting that the Blog Stats block will allow users to customise colours/fonts (one of the joys of Gutenberg!): #34557

My 2¢ as someone who has used the Blog Stats widget across multiple themes for probably eight or nine years: I always quite liked the simplicity of it, and never once considered adding my own styles. The only thing that sometimes felt weird depending on themes was the list icon appearing when it's not really a list.