assistant2: Add ability to configure tools for profiles in the UI (#27562)

This PR adds the ability to configure tools for a profile in the UI:


https://github.com/user-attachments/assets/16642f14-8faa-4a91-bb9e-1d480692f1f2

Note: Doesn't yet work for customizing tools for the default profiles.

Release Notes:

- N/A

crates/ui/src/components/navigable.rs

@@ -2,6 +2,7 @@ use crate::prelude::*;
 use gpui::{AnyElement, FocusHandle, ScrollAnchor, ScrollHandle};
 
 /// An element that can be navigated through via keyboard. Intended for use with scrollable views that want to use
+#[derive(IntoElement)]
 pub struct Navigable {
     child: AnyElement,
     selectable_children: Vec<NavigableEntry>,