Bind Swift's WidgetCenter.reloadAllTimelines

This is a suggestion to manually bind [WidgetKit.WidgetCenter.reloadAllTimelines()](https://developer.apple.com/documentation/widgetkit/widgetcenter/reloadalltimelines()) like we bound StoreKit.AppStore.requestReview: https://github.com/xamarin/xamarin-macios/commit/34d1fca7f6aa1e92d9954b5740806806527b3edf.

The exact Swift code to bind is

```swift
WidgetCenter.shared.reloadAllTimelines()
```

This should be fairly simple (most of https://github.com/xamarin/xamarin-macios/commit/34d1fca7f6aa1e92d9954b5740806806527b3edf is boiler plate code which it won't be necessary to duplicate).