Upgrade packages

Update namespaces
Clean up unused imports
Replace Avalonia.ReactiveUI with ReactiveUI.Avalonia 🙄

src/Artemis.UI/Screens/ProfileEditor/Panels/DisplayCondition/DisplayConditionScriptViewModel.cs

@@ -1,6 +1,6 @@
 using System.Collections.ObjectModel;
 using System.Linq;
-using System.Reactive.Disposables;
+using System.Reactive.Disposables.Fluent;
 using System.Reactive.Linq;
 using Artemis.Core;
 using Artemis.UI.DryIoc.Factories;