docs: update storage analytics guide example for pyiceberg (#46762)

## Summary

Updates the PyIceberg installation instruction to use the
`supabase[iceberg]` extras instead of listing dependencies separately.

## Change

**`apps/docs/content/guides/storage/analytics/examples/pyiceberg.mdx`**
— Replace `pip install pyiceberg pyarrow` with `pip install
"supabase[iceberg]"`. The `pyiceberg` dependency is optional in
`supabase-py` v2.31.0 and is now declared under
`[project.optional-dependencies]` in the package — users should use the
extras syntax rather than installing dependencies outside of the
`supabase` package.

---

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Updated installation instructions for the Iceberg storage analytics
integration guide to reflect the recommended package installation
method.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

apps/docs/content/guides/storage/analytics/examples/pyiceberg.mdx

@@ -13,7 +13,7 @@ PyIceberg is a Python client for Apache Iceberg that enables programmatic intera
 ## Installation
 
 ```bash
-pip install pyiceberg pyarrow
+pip install "supabase[iceberg]"
 ```
 
 ## Basic setup