### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

13.0.0-beta.16

### What operating system are you using?

macOS

### Operating System Version

macOS Big Sur 11.2.1

### What arch are you using?

x64

### Last Known Working Electron version

12.0.5

### Expected Behavior

When viewing a window in mission control the shadow shouldn't change.

### Actual Behavior

When viewing a window with vibrancy set to 'under-window' and titleBarStyle set to 'hidden' or 'hiddenInset' in mission control the shadow of the window is too small. 

It only seems to happen when the window is in focus and when there are multiple windows on the screen. The behaviour can sometimes persist when going from mission control to normal view. 

See the window at the bottom left in the screenshot.

<img width="1195" alt="Screenshot" src="https://user-images.githubusercontent.com/54709288/115758066-a397f980-a396-11eb-9ecc-c97e670b3b82.png">



### Testcase Gist URL

_No response_
shell/browser/native_window_mac.h
private:
  
  void AddContentViewLayers();
  void InternalSetWindowButtonVisibility(bool visible);
  void InternalSetStandardButtonsVisibility(bool visible);
  void InternalSetParentWindow(NativeWindow* parent, bool attach);
  void SetForwardMouseMessages(bool forward);
  ElectronNSWindow* window_;  
  base::scoped_nsobject<ElectronNSWindowDelegate> window_delegate_;
  base::scoped_nsobject<ElectronPreviewItem> preview_item_;
  base::scoped_nsobject<ElectronTouchBar> touch_bar_;
  base::scoped_nsobject<WindowButtonsView> buttons_view_;
  
  id wheel_event_monitor_;
  
  
  
  base::scoped_nsobject<NSView> container_view_;
  
  std::unique_ptr<RootViewMac> root_view_;
  bool is_kiosk_ = false;
  bool zoom_to_page_width_ = false;
  bool resizable_ = true;
  base::Optional<gfx::Point> traffic_light_position_;
  std::queue<bool> pending_transitions_;
  FullScreenTransitionState fullscreen_transition_state() const {
    return fullscreen_transition_state_;
  }
  FullScreenTransitionState fullscreen_transition_state_ =
      FullScreenTransitionState::NONE;