LibGUI+WindowServer: Remove now-obsolete cursor tracking feature

This feature was problematic for several reasons:
- Tracking *all* the user activity seems like a privacy nightmare.
- LibGUI actually only supports one globally tracking widget per window,
  even if no window is necessary, or if multiple callbacks are desired.
- Widgets can easily get confused whether an event is actually directed
  at it, or is actually just the result of global tracking.

The third item caused an issue where right-clicking CatDog opened two
context menus instead of one.

Userland/Services/WindowServer/ClientConnection.cpp

@@ -653,16 +653,6 @@ void ClientConnection::set_window_backing_store(i32 window_id, [[maybe_unused]]
         window.invalidate(false);
 }
 
-void ClientConnection::set_global_cursor_tracking(i32 window_id, bool enabled)
-{
-    auto it = m_windows.find(window_id);
-    if (it == m_windows.end()) {
-        did_misbehave("SetGlobalCursorTracking: Bad window ID");
-        return;
-    }
-    it->value->set_global_cursor_tracking_enabled(enabled);
-}
-
 void ClientConnection::set_global_mouse_tracking(bool enabled)
 {
     m_does_global_mouse_tracking = enabled;

Userland/Services/WindowServer/ClientConnection.h

@@ -113,7 +113,6 @@ private:
     virtual Messages::WindowServer::GetAppletRectOnScreenResponse get_applet_rect_on_screen(i32) override;
     virtual void invalidate_rect(i32, Vector<Gfx::IntRect> const&, bool) override;
     virtual void did_finish_painting(i32, Vector<Gfx::IntRect> const&) override;
-    virtual void set_global_cursor_tracking(i32, bool) override;
     virtual void set_global_mouse_tracking(bool) override;
     virtual void set_window_opacity(i32, float) override;
     virtual void set_window_backing_store(i32, i32, i32, IPC::File const&, i32, bool, Gfx::IntSize const&, bool) override;

Userland/Services/WindowServer/WindowManager.cpp

@@ -1201,12 +1201,6 @@ void WindowManager::process_mouse_event(MouseEvent& event)
         return;
 
     // 2. Send the mouse event to all clients with global cursor tracking enabled.
-    auto& window_stack = current_window_stack();
-    for_each_visible_window_from_front_to_back([&](Window& window) {
-        if (window.global_cursor_tracking() && &window != window_stack.active_input_tracking_window())
-            deliver_mouse_event(window, event, false);
-        return IterationDecision::Continue;
-    });
     ClientConnection::for_each_client([&](ClientConnection& conn) {
         if (conn.does_global_mouse_tracking()) {
             conn.async_track_mouse_move(event.position());

Userland/Services/WindowServer/WindowServer.ipc

@@ -74,7 +74,6 @@ endpoint WindowServer
     invalidate_rect(i32 window_id, Vector<Gfx::IntRect> rects, bool ignore_occlusion) =|
     did_finish_painting(i32 window_id, Vector<Gfx::IntRect> rects) =|
 
-    set_global_cursor_tracking(i32 window_id, bool enabled) =|
     set_global_mouse_tracking(bool enabled) =|
     set_window_opacity(i32 window_id, float opacity) =|