Toggle & Switch (#21979)

![CleanShot 2024-12-13 at 11 27
39@2x](https://github.com/user-attachments/assets/7c7828c0-c5c7-4dc6-931e-722366d4f15a)

- Adds the Switch component
- Updates `Selected`, `Selectable` -> `ToggleState`, `Toggleable`
- Adds `checkbox` and `switch` functions to align better with other
elements in our layout system.

We decided not to merge Switch and Checkbox. However, in a followup I'll
introduce a Toggle or AnyToggle enum so we can update
`CheckboxWithLabel` -> `ToggleWithLabel` as this component will work
exactly the same with either a Checkbox or a Switch.

Release Notes:

- N/A

crates/assistant/src/slash_command_picker.rs

@@ -176,7 +176,7 @@ impl PickerDelegate for SlashCommandDelegate {
                 ListItem::new(ix)
                     .inset(true)
                     .spacing(ListItemSpacing::Dense)
-                    .selected(selected)
+                    .toggle_state(selected)
                     .tooltip({
                         let description = info.description.clone();
                         move |cx| cx.new_view(|_| Tooltip::new(description.clone())).into()
@@ -229,7 +229,7 @@ impl PickerDelegate for SlashCommandDelegate {
                 ListItem::new(ix)
                     .inset(true)
                     .spacing(ListItemSpacing::Dense)
-                    .selected(selected)
+                    .toggle_state(selected)
                     .child(renderer(cx)),
             ),
         }