Fix right click handler for tabs

Also, some fun test helpers

Co-Authored-By: Mikayla <mikayla@zed.dev>

crates/ui/src/components/button/button_like.rs

@@ -293,7 +293,7 @@ impl ButtonSize {
 /// This is also used to build the prebuilt buttons.
 #[derive(IntoElement)]
 pub struct ButtonLike {
-    base: Div,
+    pub base: Div,
     id: ElementId,
     pub(super) style: ButtonStyle,
     pub(super) disabled: bool,