### 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
void ShowInactive() override;
  void Hide() override;
  bool IsVisible() override;
  bool IsEnabled() override;
  void SetEnabled(bool enable) override;
  void Maximize() override;
  void Unmaximize() override;
  bool IsMaximized() override;
  void Minimize() override;
  void Restore() override;
  bool IsMinimized() override;
  void SetFullScreen(bool fullscreen) override;
  bool IsFullscreen() const override;
  void SetBounds(const gfx::Rect& bounds, bool animate = false) override;
  gfx::Rect GetBounds() override;
  bool IsNormal() override;
  gfx::Rect GetNormalBounds() override;
  void SetContentSizeConstraints(
      const extensions::SizeConstraints& size_constraints) override;
  void SetResizable(bool resizable) override;
  bool MoveAbove(const std::string& sourceId) override;
  void MoveTop() override;
  bool IsResizable() override;
  void SetMovable(bool movable) override;
  bool IsMovable() override;
  void SetMinimizable(bool minimizable) override;
  bool IsMinimizable() override;
  void SetMaximizable(bool maximizable) override;
  bool IsMaximizable() override;
  void SetFullScreenable(bool fullscreenable) override;