fix: correct InvalidCustomPropertyError code and MemoryStore promise handling (#2853)

Author: KirobotDev

src/conversation-store.ts

@@ -36,8 +36,10 @@ export class MemoryStore<ConversationState = any> implements ConversationStore<C
           // release the memory
           this.state.delete(conversationId);
           reject(new Error('Conversation expired'));
+          return;
         }
         resolve(entry.value);
+        return;
       }
       reject(new Error('Conversation not found'));
     });

src/errors.ts

@@ -106,7 +106,7 @@ export class ContextMissingPropertyError extends Error implements CodedError {
 }
 
 export class InvalidCustomPropertyError extends Error implements CodedError {
-  public code = ErrorCode.AppInitializationError;
+  public code = ErrorCode.InvalidCustomPropertyError;
 }
 
 export class CustomRouteInitializationError extends Error implements CodedError {