This PR increases the spacing of `ListItem`s inside of `Picker`s to give
the UI some more breathing room.

#### Before

<img width="584" alt="Screenshot 2023-12-21 at 4 36 21 PM"
src="https://github.com/zed-industries/zed/assets/1486634/ed324c0d-e606-4844-b30a-7d5b8b8c9e47">

#### After

<img width="592" alt="Screenshot 2023-12-21 at 4 36 31 PM"
src="https://github.com/zed-industries/zed/assets/1486634/fbbcb230-0048-4310-8e06-07943af6a38e">

Release Notes:

- N/A