Update egui_commonmark to 0.9 (#3882)

### What

Gives us copy button in code blocks:

<img width="1190" alt="image"
src="https://github.com/rerun-io/rerun/assets/49431240/b6c30e4c-9e0b-4312-a908-652cc6d424e2">

Note: copy/paste seems to not work from web/Safari
emilk/egui#3480.


### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/3882) (if
applicable)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/3882)
- [Docs
preview](https://rerun.io/preview/79bc94fd4e913f5f2c6eb185c08089f2d2d654ee/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/79bc94fd4e913f5f2c6eb185c08089f2d2d654ee/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://ref.rerun.io/dev/bench/)
- [Wasm size tracking](https://ref.rerun.io/dev/sizes/)

Cargo.toml

@@ -106,7 +106,7 @@ egui = { version = "0.23.0", features = [
   "log",
   "puffin",
 ] }
-egui_commonmark = { version = "0.8", default-features = false }
+egui_commonmark = { version = "0.9", default-features = false }
 egui_extras = { version = "0.23.0", features = ["http", "image", "puffin"] }
 egui_plot = "0.23.0"
 egui_tiles = "0.3.1"