Fix comment preview spacing

[bryophyta]

What does this change?

It adds bottom margin to paragraph tags.

Why?

This makes the styling in comment previews more consistent with the styling of submitted comments. This should address the first part of this issue.

Screenshots

(From storybook)

Before in Prod	Before in storybook	After in storybook

Previously, the storybook rendering of comment previews didn't match the production site, because the dotcom site applies reset styles which weren't being applied in storybook. This PR adds the reset styles (globally, merging #572) and also adds spacing to the preview comments. So there shouldn't be much visual change in the storybook itself, but the storybook should now match dotcom.

[github-actions]

Size Change: +219 B (0%)

Total Size: 218 kB

Filename	Size	Change
build/App.esm.js	109 kB	+118 B (0%)
build/App.js	109 kB	+101 B (0%)

_{compressed-size-action}

[jlieb10]

LGTM - just wondering where the padding and width figures come from?

[bryophyta]

LGTM - just wondering where the padding and width figures come from?

The ones in the story components? I took them from the stories for CommentBlockComponents, where there was already the padding, and then Oliver suggested adding a width: https://github.com/guardian/dotcom-rendering/pull/4838/files#r866602666

I thought these seemed fairly appropriate here too, but to be honest I didn't give it too much thought, so happy to adapt if you think it suitable 👍

[oliverlloyd]

Nice 👍

[bryophyta]

Thanks! I'll merge now.

@oliverlloyd, I don't think I have the required permissions to publish the package to npm. I'm not sure how often we release updates to the package, but I'd be interested in going through the publishing process with someone next time it's released.