chore: remove example code (#32)

Author: jaeho614

src/components/Counter.tsx

@@ -1,13 +1,11 @@
 import { configureStore } from '@reduxjs/toolkit';
-import counterReducer from './slices/counterSlice'; // 예시 import
 import signupReducer from './slices/signup-slice';
 import signupAddressReducer from './slices/signup-address-slice';
 import themeReducer from './slices/themeSlice';
 import { themeApi } from './api/themeApi';
 
 export const store = configureStore({
   reducer: {
-    counter: counterReducer, // 예시
     signup: signupReducer,
     signupAddress: signupAddressReducer,
     theme: themeReducer,