Disconnect Dialog: handle extremely large numbers

* Start from a connected Jetpack site, where the Stats module is active and you've had visitors already.
* In Jetpack > Dashboard, click on the link to manage the site connection.
* In the modal that opens, if the stats has a lot of stats, the layout may break:

* The same holds true for other cards.

Maybe we should make sure that when we have huge numbers, we switch to a different format, like maybe letters like `k` for thousands?

Start from a connected Jetpack site with the Stats module active, then reproduce the layout break through Jetpack > Dashboard and the site-connection management link. Inspect the Disconnect Dialog and its cards, including the Stats card, and verify that very large values no longer break the modal layout and are displayed in a readable compact format.

Written by the indexing model from the issue text.