Improve CSS token documentation in Storybook

[hannahblair]

Description

This PR adds a few more stories with the css variables we use. It also removes hardcoded widths and heights for any icons and moves that sizing to their respective component. This improves the icons story a bit more.

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Tests

1. PRs will only be merged if tests pass on CI. To run the tests locally, please set up your Gradio environment locally and run the tests: bash scripts/run_all_tests.sh

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[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
	Website	ready!	Website preview
	Storybook	ready!	Storybook preview
	Visual tests	all good!	Build review
🦄	Changes	detected!	Details

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/19c5c408c7de4add1e46385ab492eb1eac4e7dd8/gradio-4.8.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@19c5c408c7de4add1e46385ab492eb1eac4e7dd8#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/chatbot	patch
@gradio/dropdown	patch
@gradio/icons	patch
@gradio/image	patch
@gradio/row	patch
gradio	patch

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With the following changelog entry.

Improve CSS token documentation in Storybook

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[abidlabs]

@hannahblair can you explain the addition of the ShadowRow and TokenRow -- what do they achieve?

A few things I was unsure about:

1. In the Shadows section, there's a box with "Gradio" written in it. Clicking on it copies the token, but that's not super intuitive to me:

2. In the Row Layout, I think there should be two images side by side, but none show up:

[hannahblair]

@hannahblair can you explain the addition of the ShadowRow and TokenRow -- what do they achieve?

A few things I was unsure about:

1. In the Shadows section, there's a box with "Gradio" written in it. Clicking on it copies the token, but that's not super intuitive to me:

2. In the Row Layout, I think there should be two images side by side, but none show up:

Ah the trusty groot file is broken now! I've replaced the broken link with an image from our AWS bucket in the Row story and a couple others. I also meant to remove the Shadows story and the TokenRow component; they're not needed now as we'll take a more user friendly approach to documenting these css vars.