Improve chatbot accessibility and UX (#5699)
* add a11y changes and css tweaks
* add a11y changes and css tweaks
* change like/dislike/copy buttons ux
* cleanup
* add laout param
* tweak
* add changeset
* fill icon on click
* text alignment tweak
* format + test
* fix browser test
* avatar tweaks
* add stories
* tweak
* tweak
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Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>
