Fixed issue with Horizontal list not refreshing. Added clientId to joinPartyResponse. Crashing on multiple user joins.

Aurora/Design/Components/HorizontalList/HorizontalList.cs

@@ -25,10 +25,10 @@ namespace Aurora.Design.Components.HorizontalList
 
         public static readonly BindableProperty ItemsSourceProperty =
             BindableProperty.Create("ItemsSource",
-                typeof(ObservableCollection<object>),
-                typeof(HorizontalList),
-                default(ObservableCollection<object>),
-                BindingMode.TwoWay,
+                returnType: typeof(ObservableCollection<object>),
+                declaringType: typeof(HorizontalList),
+                defaultValue: default(ObservableCollection<object>),
+                defaultBindingMode: BindingMode.TwoWay,
                 propertyChanged: ItemsSourceChanged);
 
         public static readonly BindableProperty SelectedItemProperty =