Fix edit prediction disablement with "disable_ai": true setting (#35513)

Even after #35327 edit predictions were still being queried and shown
after setting `"disable_ai": true`

Also moves `DisableAiSettings` to the `project` crate so that it gets
included in tests via existing use of `Project::init_settings(cx)`.

Release Notes:

- Fixed `"disable_ai": true` setting disabling edit predictions.

Cargo.lock

@@ -6315,7 +6315,6 @@ dependencies = [
  "buffer_diff",
  "call",
  "chrono",
- "client",
  "cloud_llm_client",
  "collections",
  "command_palette_hooks",