Add support to dismiss the prompt with enter on keyboard (#27419)

* add support to dismiss the prompt with enter on keyboard

* Windows only

---------

Co-authored-by: Gerald Versluis <gerald.versluis@microsoft.com>

Author: pictos

src/Controls/src/Core/Platform/AlertManager/AlertManager.Windows.cs

@@ -143,7 +143,8 @@ async void OnPromptRequested(Page sender, PromptArguments arguments)
 					Input = arguments.InitialValue ?? string.Empty,
 					Placeholder = arguments.Placeholder ?? string.Empty,
 					MaxLength = arguments.MaxLength >= 0 ? arguments.MaxLength : 0,
-					InputScope = arguments.Keyboard.ToInputScope()
+					InputScope = arguments.Keyboard.ToInputScope(),
+					DefaultButton = ContentDialogButton.Primary
 				};
 
 				if (arguments.Cancel != null)