Fix crash when using Yubikey via usb on Android (#1246)

* Fix crash when using yubikey via usb on Android

* Fix crash when using usb keyboard on Android

src/Android/MainActivity.cs

@@ -27,7 +27,9 @@ namespace Bit.Droid
         Icon = "@mipmap/ic_launcher",
         Theme = "@style/LaunchTheme",
         MainLauncher = true,
-        ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
+        ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation |
+                               ConfigChanges.Keyboard | ConfigChanges.KeyboardHidden |
+                               ConfigChanges.Navigation)]
     [Register("com.x8bit.bitwarden.MainActivity")]
     public class MainActivity : Xamarin.Forms.Platform.Android.FormsAppCompatActivity
     {

src/App/Pages/Accounts/TwoFactorPage.xaml.cs

@@ -102,6 +102,9 @@ namespace Bit.App.Pages
                 if (_vm.TotpMethod)
                 {
                     RequestFocus(_totpEntry);
+                } else if (_vm.YubikeyMethod)
+                {
+                    RequestFocus(_yubikeyTokenEntry);
                 }
                 return Task.FromResult(0);
             });