UX: Improve blockquote styling in emails (PR #13527)

Before/after:

In-app:

GitHub

I’m obligated to ask if there’s any way you can do this without !important?

We’re inlining these styles anyway, so having it important! free doesn’t matter that much, but yeah - moving stuff around makes it so that these styles are applied first, and then all the other ones are then prepended so these take precedence.

awesome thanks!