Add InteractiveElement::block_mouse which renders an "opaque" layer

Co-Authored-By: Antonio <antonio@zed.dev>
Co-Authored-By: Max Brunsfeld <max@zed.dev>

crates/workspace2/src/dock.rs

@@ -499,7 +499,8 @@ impl Render for Dock {
                         cx.stop_propagation();
                     }
                 }))
-                .z_index(1);
+                .z_index(1)
+                .block_mouse();
 
             const HANDLE_SIZE: Pixels = Pixels(6.);