ui: Update Label component (#24653)

- Standardize style methods
- Convert label story to a component preview
- update component preview styles  

Release Notes:

- N/A

crates/project_panel/src/project_panel.rs

@@ -3994,7 +3994,7 @@ impl ProjectPanel {
                                                     .when(
                                                         index == active_index
                                                             && (is_active || is_marked),
-                                                        |this| this.underline(true),
+                                                        |this| this.underline(),
                                                     ),
                                             );