Update assistant config UI (#15630)

![CleanShot 2024-08-01 at 12 55
01@2x](https://github.com/user-attachments/assets/f9ed44ba-6bff-4805-ad71-2e3538315e57)

- Remove assisstant_description for now.
- Updates assistant config UI
- Updates Ollama and zed.dev provider UIs
- Updates download icon

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/zed/src/zed.rs

@@ -3467,7 +3467,12 @@ mod tests {
                 app_state.client.http_client().clone(),
                 cx,
             );
-            language_model::init(app_state.client.clone(), app_state.fs.clone(), cx);
+            language_model::init(
+                app_state.user_store.clone(),
+                app_state.client.clone(),
+                app_state.fs.clone(),
+                cx,
+            );
             assistant::init(app_state.fs.clone(), app_state.client.clone(), cx);
             repl::init(
                 app_state.fs.clone(),