Update puffin_egui to egui 0.24 (EmbarkStudios#166)

### Checklist

* [x] I have read the [Contributor Guide](../CONTRIBUTING.md)
* [x] I have read and agree to the [Code of
Conduct](../CODE_OF_CONDUCT.md)
* [x] I have added a description of my changes and why I'd like them
included in the section below

### Description of Changes

I also made `puffin_egui` even better with a new function
`show_viewport_if_enabled`. On supported backends (`eframe`), it will
open the puffin profiler flamegraph in its own viewport:

<img width="844" alt="Screenshot 2023-11-20 at 21 11 04"
src="https://github.com/EmbarkStudios/puffin/assets/1148717/7e06f433-b9d1-4b6f-bfc5-eeae4bef5986">

On other egui backends it will fall back to open it in a window.