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/collab_ui/src/collab_panel.rs

@@ -2947,7 +2947,7 @@ impl Render for DraggedChannelView {
     fn render(&mut self, cx: &mut ViewContext<Self>) -> impl Element {
         let ui_font = ThemeSettings::get_global(cx).ui_font.family.clone();
         h_flex()
-            .font(ui_font)
+            .font_family(ui_font)
             .bg(cx.theme().colors().background)
             .w(self.width)
             .p_1()