remove duplicate

src/Infrastructure/BotSharp.Abstraction/Models/KeyValue.cs

@@ -7,4 +7,9 @@ public class KeyValue
 
     [JsonPropertyName("value")]
     public string Value { get; set; }
+
+    public override string ToString()
+    {
+        return $"Key: {Key}, Value: {Value}";
+    }
 }

src/Infrastructure/BotSharp.Abstraction/Repositories/Filters/ConversationFilter.cs

@@ -23,15 +23,4 @@ public class ConversationFilter
     /// Check whether each key in the list is in the conversation states and its value equals to target value if not empty 
     /// </summary>
     public IEnumerable<KeyValue> States { get; set; } = new List<KeyValue>();
-}
-
-public class KeyValue
-{
-    public string Key { get; set; }
-    public string? Value { get; set; }
-
-    public override string ToString()
-    {
-        return $"Key: {Key}, Value: {Value}";
-    }
 }