git_ui: Prevent button overflow due to long names (#25940)

- Fix component preview widths for git panel
- Fix buttons getting pushed off the screen in git  panel

Release Notes:

- N/A

---------

Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>

crates/ui/src/components/label/highlighted_label.rs

@@ -64,8 +64,8 @@ impl LabelCommon for HighlightedLabel {
         self
     }
 
-    fn text_ellipsis(mut self) -> Self {
-        self.base = self.base.text_ellipsis();
+    fn truncate(mut self) -> Self {
+        self.base = self.base.truncate();
         self
     }