Mainline `Icon` and `IconButton` changes (#3022)

This PR mainlines the `Icon` and `IconButton` changes from the
`gpui2-ui` branch.

Release Notes:

- N/A

Co-authored-by: Nate Butler <nate@zed.dev>
895386cfafMarshall Bowers committed on 9/22/2023, 11:14:12 PM· committed by GitHubparentad62a96
7 files changedLine totals unavailable