This PR makes the Assistant 2 submit button have a different width if
the platform is Linux or Windows, or if Vim mode is turned on. That's
because we now use written out words instead of icons for keybindings
when in those conditions.

| Before | After |
|--------|--------|
| ![CleanShot 2025-02-27 at 9  59
10@2x](https://github.com/user-attachments/assets/f1f8e27c-71c2-402c-8f7b-f9ed91e8e3bf)
| ![CleanShot 2025-02-27 at 9  56
59@2x](https://github.com/user-attachments/assets/ad13b179-daf7-4b38-83e8-1511deb97d96)
|

Release Notes:

- N/A