Surface Dial Extension Bugs

## Describe the bug
Found a few issues with the Surface Dial TextBox Extensions:

- [ ] Tapping doesn't go to the next control (if you have focus on first box below, tap dial, then it doesn't go to next textbox)
- [x] ~Default Icon should be `Scroll` not `Ruler` as it is shown in menu (unlike the comment says) and...~ (didn't notice we're going to have scroll already by default, so I guess ruler is a good compromise unless we added a custom icon...
- [ ] Is `ForceMenuItem` required for this to work? It seems to be which is odd...
- [ ] Copy the TextBox in the sample and you'll see there's two (or more!) menu items in the Surface Menu... (there should only ever be a single one).


## Steps to Reproduce

Sample App:
```xml

```

## Expected behavior
Tapping should go to the next tab order control. Menu item should only appear a single time ever when the textbox has focus. If it can work without the `ForceMenuItem` property it should, otherwise this property seems useless, should it just be `ShowMenuItem`?

## Environment
Existing 6.1 Sample App.

Commencez avec la Existing 6.1 Sample App et reproduisez les comportements non vérifiés de SurfaceDialTextbox à l’aide du XAML fourni : navigation par appui, gestion de ForceMenuItem et éléments de menu en double. Examinez les points d’entrée d’extension et les propriétés attachées de SurfaceDialTextbox mentionnés dans l’exemple. C’est terminé lorsqu’un appui passe au contrôle suivant dans l’ordre de tabulation et que la TextBox ayant le focus ne contribue qu’à un seul élément de menu correctement configuré.

Rédigé par le modèle d'indexation à partir du texte de l'issue.