fix deletion secret and token if cancel

src/client/js/components/Admin/SlackIntegration/SlackIntegration.jsx

@@ -69,10 +69,6 @@ const SlackIntegration = (props) => {
       setCurrentBotType(clickedBotType);
       return;
     }
-    setIsRegisterSlackCredentials(false);
-    setSlackSigningSecret('');
-    setSlackBotToken('');
-    setIsSendTestMessage('');
     setSelectedBotType(clickedBotType);
   };