Closes #50977

Before you mark this PR as ready for review, make sure that you have:
- [x] Added a solid test coverage and/or screenshots from doing manual
testing
- [x] Done a self-review taking into account security and performance
aspects
- [x] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Before:
<img width="1700" height="1063" alt="image"
src="https://github.com/user-attachments/assets/fd8e8438-a8a8-4d00-ac72-7e5ab75c8723"
/>

After:
<img width="1700" height="1066" alt="image"
src="https://github.com/user-attachments/assets/e31e449d-93ce-433e-94fd-cfdc08d61f49"
/>


Release Notes:

- Fixed kernels discovery in python notebook editor.

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Co-authored-by: Finn Evers <finn@zed.dev>