Adds a `gr.DownloadButton` component (#7518)
* py
* path
* barebones js
* add changeset
* add changeset
* downloadbutton
* add changeset
* changes
* clog
* commit
* revert'
* fix
* js
* add changeset
* cleanup
* download
* notebooks
* stories
* change
* fix
* format
* download
* Fix updating `icon` parameter (bug resulting from https://github.com/gradio-app/gradio/pull/7528) (#7554)
* fetch 2
* fix
---------
Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>
