wayland: Implement xdg-activation when opening urls (#11368)

Since Wayland doesn't have a way for windows to activate themselves,
currently, when you click on a link in Zed, the browser window opens in
the background.

This PR implements the `xdg-activation` protocol to get an activation
token, which the browser can use to raise its window.


https://github.com/zed-industries/zed/assets/71973804/8b3456c0-89f8-4201-b1cb-633a149796b7

Release Notes:

- N/A

crates/gpui/src/platform/linux/wayland/window.rs

@@ -251,6 +251,10 @@ impl WaylandWindow {
 }
 
 impl WaylandWindowStatePtr {
+    pub fn surface(&self) -> wl_surface::WlSurface {
+        self.state.borrow().surface.clone()
+    }
+
     pub fn ptr_eq(&self, other: &Self) -> bool {
         Rc::ptr_eq(&self.state, &other.state)
     }