Add comments for ScenarioStateStore related code (#1433)

src/WireMock.Net.Abstractions/Handlers/IScenarioStateStore.cs

@@ -1,7 +1,5 @@
 // Copyright © WireMock.Net
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 
 namespace WireMock.Handlers;
@@ -23,4 +21,4 @@ public interface IScenarioStateStore
     bool TryRemove(string name);
 
     void Clear();
-}
+}