Remove duplicate NetP notifications (#2057)

Task/Issue URL: https://app.asana.com/0/0/1205617766971743/f

Description:

On introducing notifications to NetP, I noticed that they were a big noisy. This PR can be merged to deal with that if we agree.

PacketTunnelProvider/NetworkProtection/NetworkProtectionUNNotificationPresenter.swift

@@ -101,7 +101,7 @@ final class NetworkProtectionUNNotificationPresenter: NSObject, NetworkProtectio
             guard authorized else {
                 return
             }
-
+            self.userNotificationCenter.removeDeliveredNotifications(withIdentifiers: [identifier.rawValue])
             self.userNotificationCenter.add(request)
         }
     }