Core: Add global box-sizing setting. Fixes #10207

[matheo]

Issue: #10207

@shilman any other way to set this global style? or this is fine?

[shilman]

@matheo i think this is a @ndelangen question :)

[ndelangen]

I think this might be a better place for it.

storybook/lib/theming/src/global.ts

Lines 100 to 113 in c5f5208

	...resetStyles,
	body: {
	...resetStyles.body,
	color: color.defaultText,
	background: background.app,
	overflow: 'hidden',
	},
	hr: {
	...resetStyles.hr,
	borderTop: `1px solid ${color.border}`,
	},
	};
	}

I foresee a problem with this though:

We render storybook UI components in 2 places: In the manager and in addon-docs.

This change will be problematic for the latter.

If our UI components start expecting to be rendered with these global styles, (which will potentially not be the case in addon-docs) this could cause problems for us.

Can we fix #10207 in another more specific method?

[matheo]

@ndelangen a global reset seems to be better. See #11071

[shilman]

@matheo @ndelangen any chance we can push this forward in the next few days?