This fixes a major degradation in usability that some users ran into.

Fixes https://github.com/zed-industries/zed/issues/8255 
Fixes https://github.com/zed-industries/zed/issues/8229

Release Notes:

- Switch from using platform prompts to toasts for LSP prompts.
([8255](https://github.com/zed-industries/zed/issues/8255),
[8229](https://github.com/zed-industries/zed/issues/8229))

<img width="583" alt="Screenshot 2024-02-23 at 2 40 05 PM"
src="https://github.com/zed-industries/zed/assets/2280405/1bfc027b-b7a8-4563-88b6-020e47869668">

Co-authored-by: Marshall <marshall@zed.dev>