chore: Prepare for Rust edition bump to 2024 (without autofix) (#27791)

Successor to #27779 - in this PR I've applied changes manually, without
futzing with if let lifetimes at all.

Release Notes:

- N/A

crates/collab_ui/src/chat_panel.rs

@@ -332,7 +332,7 @@ impl ChatPanel {
                                     .color(Color::Muted),
                             )
                         }),
-                )
+                );
             }
             Some(val) => val,
         };