New revision of the Assistant Panel (#10870)

This is a crate only addition of a new version of the AssistantPanel.
We'll be putting this behind a feature flag while we iron out the new
experience.

Release Notes:

- N/A

---------

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Conrad Irwin <conrad@zed.dev>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>
Co-authored-by: Antonio Scandurra <antonio@zed.dev>
Co-authored-by: Nate Butler <nate@zed.dev>
Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Max <max@zed.dev>

crates/storybook/src/story_selector.rs

@@ -29,14 +29,14 @@ pub enum ComponentStory {
     ListHeader,
     ListItem,
     OverflowScroll,
+    Picker,
     Scroll,
     Tab,
     TabBar,
+    Text,
     TitleBar,
     ToggleButton,
-    Text,
     ViewportUnits,
-    Picker,
 }
 
 impl ComponentStory {