Wayland: Fix fallback decoration cursor updating

When a click through to the fallback decorations caused the end of
a modal like the window menu, the cursor shape would not be updated
until the next time the cursor moved.

This commit adds an update of the cursor for the pointer enter event for
fallback decoration surfaces, in addition to the updates at pointer
motion events.

src/wl_window.c

@@ -1542,7 +1542,10 @@ static void pointerHandleEnter(void* userData,
     else
     {
         if (window->wl.fallback.decorations)
+        {
             window->wl.fallback.focus = surface;
+            updateFallbackDecorationCursor(window, sx, sy);
+        }
     }
 }