fix(addons-info): change stylesheetBase info height from 110vh to 100vh

[jendowns]

Resolves #7140

What I did

In this case, changing the height from 110vh to 100vh fixes the issue identified in #7140, where the last propTypes table in a given "Info" pane/section gets cut off for any component you view.

Please let me know if you need more info from me about this issue, if you disagree, or if you prefer a different fix.

We identified this issue originally in our internal storybook when upgrading from the stable release to v5.2.0-alpha.28 (in order to get the code block fixes 😅 )

How to test

1. Check out this page in the PR deployment, for example: https://monorepo-git-fork-jendowns-patch-2.storybook.now.sh/examples/official-storybook/?path=/story/addons-info-markdown--displays-markdown-in-description
2. Click "show info" and reduce your browser window height a bit so you get a scrollbar in the Info pane
3. Scroll down, note that the last part of the propTypes table looks fine
4. Inspect the "Info" pane & find the .info__overlay element
5. Change height: 100vh to height: 110vh (previous value)
6. Scroll up and down, note that the propTypes table is cut off at the bottom of the Info pane

[vercel]

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Latest deployment for this branch: https://monorepo-git-fork-jendowns-patch-2.storybook.now.sh

[shilman]

LGTM! Thanks!!