Closes #38200

Applied
[suggestion](https://github.com/zed-industries/zed/issues/38200#issuecomment-3354159899)
from issue to use `-l -e` instead of `-l -i -c` when running on nushell
because of how it treats `-l` as implying interactive session. Using
`-e` also means that command needs to end with `exit` to terminate shell
manually. With this changes everything now works fine in my testing.

Before, zed fails to load environment variables and there is error in
logs:

<img width="367" height="92" alt="image"
src="https://github.com/user-attachments/assets/9ef08d06-a509-4c96-85fe-8291bfc95b39"
/>

<img width="1711" height="115" alt="image"
src="https://github.com/user-attachments/assets/fe3a6248-6f73-4773-a2c8-db55a95aaec1"
/>

With this patch everything works fine and all language servers and stuff
loads fine:

<img width="565" height="73" alt="image"
src="https://github.com/user-attachments/assets/7477913d-42f9-41b0-a7b6-92831f406be4"
/>

Tested on nixos unstable. Nushell version 0.110.0 and 0.111.0. Zed
version 0.223.3+stable and compiled from main fail. Zed from this branch
works.

Release Notes:

- Fixed loading environment variables when nushell is used as shell