Meta - Fixed a bunch of build warnings

src/Artemis.UI/Screens/Workshop/Home/WorkshopOfflineViewModel.cs

@@ -1,10 +1,8 @@
-
+using System;
 using System.Reactive;
 using System.Threading;
 using System.Threading.Tasks;
-using Artemis.UI.Shared;
 using Artemis.UI.Shared.Routing;
-using Artemis.WebClient.Workshop;
 using Artemis.WebClient.Workshop.Services;
 using ReactiveUI;
 
@@ -14,7 +12,7 @@ public class WorkshopOfflineViewModel : RoutableScreen<WorkshopOfflineParameters
 {
     private readonly IRouter _router;
     private readonly IWorkshopService _workshopService;
-    private string _message;
+    private string _message = string.Empty;
 
     /// <inheritdoc />
     public WorkshopOfflineViewModel(IWorkshopService workshopService, IRouter router)
@@ -51,5 +49,5 @@ public class WorkshopOfflineViewModel : RoutableScreen<WorkshopOfflineParameters
 
 public class WorkshopOfflineParameters
 {
-    public string Message { get; set; }
+    public string Message { get; set; } = string.Empty;
 }