test: move Notification spec to main process (#19414)

docs/api/notification.md

@@ -110,6 +110,44 @@ shown notification and create a new one with identical properties.
 
 Dismisses the notification.
 
+### Instance Properties
+
+#### `notification.title`
+
+A `String` property representing the title of the notification.
+
+#### `notification.subtitle`
+
+A `String` property representing the subtitle of the notification.
+
+#### `notification.body`
+
+A `String` property representing the body of the notification.
+
+#### `notification.replyPlaceholder`
+
+A `String` property representing the reply placeholder of the notification.
+
+#### `notification.sound`
+
+A `String` property representing the sound of the notification.
+
+#### `notification.closeButtonText`
+
+A `String` property representing the close button text of the notification.
+
+#### `notification.silent`
+
+A `Boolean` property representing whether the notification is silent.
+
+#### `notification.hasReply`
+
+A `Boolean` property representing whether the notification has a reply action.
+
+#### `notification.actions`
+
+A [`NotificationAction[]`](structures/notification-action.md) property representing the actions of the notification.
+
 ### Playing Sounds
 
 On macOS, you can specify the name of the sound you'd like to play when the