Updated radix-ui example to use App Router (#68711)
This PR updates the radix-ui example to use the App Router. Here are the
changes that have been made:
Renamed the "pages" folder to "app" folder.
Updated the file index.tsx to page.tsx to align with App Router.
Added the layout.tsx file as part of the App Router.
Updated the paths to the files that will use Tailwind CSS class names as
per "app" folder in tailwind config file
Updated package.json to use the latest version.
cc: @samcx
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Co-authored-by: ShruthiKathula <147117812+ShruthiKathula@users.noreply.github.com>
Co-authored-by: Sam Ko <sam@vercel.com>
