Small code refactoring.

src/Squidex.Domain.Apps.Entities/Apps/AppGrain.cs

@@ -196,16 +196,14 @@ namespace Squidex.Domain.Apps.Entities.Apps
                         {
                             var result = await appPlansBillingManager.ChangePlanAsync(c.Actor.Identifier, Snapshot.Id, Snapshot.Name, c.PlanId);
 
-                            if (result is PlanChangedResult)
+                            switch (result)
                             {
-                                if (result is PlanResetResult)
-                                {
-                                    ResetPlan(c);
-                                }
-                                else
-                                {
+                                case PlanChangedResult _:
                                     ChangePlan(c);
-                                }
+                                    break;
+                                case PlanResetResult _:
+                                    ResetPlan(c);
+                                    break;
                             }
 
                             return result;

src/Squidex.Domain.Apps.Entities/Apps/Services/PlanChangedResult.cs

@@ -7,7 +7,7 @@
 
 namespace Squidex.Domain.Apps.Entities.Apps.Services
 {
-    public class PlanChangedResult : IChangePlanResult
+    public sealed class PlanChangedResult : IChangePlanResult
     {
     }
 }

src/Squidex.Domain.Apps.Entities/Apps/Services/PlanResetResult.cs

@@ -7,7 +7,7 @@
 
 namespace Squidex.Domain.Apps.Entities.Apps.Services
 {
-    public class PlanResetResult : PlanChangedResult
+    public sealed class PlanResetResult : IChangePlanResult
     {
     }
 }