Update WebPreferences's ContextIsolation default value to true

Author: Yuvix25

src/ElectronNET.API/Entities/WebPreferences.cs

@@ -185,7 +185,7 @@ public class WebPreferences
         /// Context' entry in the combo box at the top of the Console tab. This option is
         /// currently experimental and may change or be removed in future Electron releases.
         /// </summary>
-        [DefaultValue(false)]
+        [DefaultValue(true)]
         public bool ContextIsolation { get; set; } = false;
 
         /// <summary>