Add copy button to gr.Markdown

[hannahblair]

Description

Adds a copy button to the markdown component.

Closes: #8642

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Tests

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[gradio-pr-bot]

🪼 branch checks and previews

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/8a644418d36e331af7389d7823a9940d2e79f4f4/gradio-4.38.1-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@8a644418d36e331af7389d7823a9940d2e79f4f4#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-builds.s3.amazonaws.com/8a644418d36e331af7389d7823a9940d2e79f4f4/gradio-client-1.3.0.tgz

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/markdown	minor
gradio	minor

• Maintainers can select this checkbox to manually select packages to update.

With the following changelog entry.

Add copy button to gr.Markdown

Maintainers or the PR author can modify the PR title to modify this entry.

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[abidlabs]

LGTM thanks @hannahblair!!

[abidlabs]

One thing I'm curious about is why all of the stories (e.g. https://www.chromatic.com/test?appId=649585a46a67480e3074dc75&id=669ab3271c55d38fbbe39778) include the copy button even though the default value of show_copy_button is false?

[hannahblair]

thanks @abidlabs, fixed!