servoshell: Implement context menu in servoshell (#40434)

This PR adds context menu support with clickable menu items in the
Minibrowser. The menu appears on right click and supports basic
navigation actions (Back, Forward, Reload).


Testing: We already have tests for ContextMenu in WebView API test.

Signed-off-by: atbrakhi <atbrakhi@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>

components/script/dom/html/htmlselectelement.rs

@@ -398,6 +398,7 @@ impl HTMLSelectElement {
             .show_embedder_control(
                 ControlElement::Select(DomRoot::from_ref(self)),
                 EmbedderControlRequest::SelectElement(options, selected_index),
+                None,
             );
     }