Bug fix escape 'about page' is breaking on fullscreen mode [macOS] (#4619)

* Remove main window as parent from about window
* Remove previous code to fix 4540

Co-authored-by: Harrison Bronfeld <harrisonbronfeld@Harrisons-MacBook-Air.local>

main.js

@@ -663,7 +663,6 @@ function showAbout() {
       preload: path.join(__dirname, 'about_preload.js'),
       nativeWindowOpen: true,
     },
-    parent: mainWindow,
   };
 
   aboutWindow = new BrowserWindow(options);