add check login

src/js/09-check-login.js

-// eslint-disable-next-line no-undef
+/* eslint-disable no-undef */
+function removeSecretNav () {
+  const elements = document.getElementsByClassName('secret-nav')
+  while (elements.length > 0) {
+    elements[0].parentNode.removeChild(elements[0])
+  }
+}
+
 fetch('/web/dms/api/auth/status')
   .then((response) => {
     if (response.url === 'https://swlab.bwg.co.kr/web/dms/login') {
-      const elements = document.getElementsByClassName('secret-nav')
-      while (elements.length > 0) {
-        elements[0].parentNode.removeChild(elements[0])
-      }
+      removeSecretNav()
     }
   })
   .catch((error) => {
     console.error('Error checking login status:', error)
+    removeSecretNav()
   })