WindowServer: Fix custom cursors

Custom cursor is now only set if the cursor is in the client area
instead of anyehere in the window. This makes hidden cursor visible
when it is on top of the title bar!

userspace/programs/WindowServer/WindowServer.cpp

@@ -1355,8 +1355,8 @@ BAN::RefPtr<Window> WindowServer::find_window_with_fd(int fd) const
 
 BAN::RefPtr<Window> WindowServer::find_hovered_window() const
 {
-	for (auto window : m_client_windows)
-		if (window->full_area().contains(m_cursor))
+	for (size_t i = m_client_windows.size(); i > 0; i--)
+		if (auto window = m_client_windows[i - 1]; window->client_area().contains(m_cursor))
 			return window;
 	return {};
 }