Fix build warnings

frontend/package-lock.json

frontend/package.json

frontend/src/components/SideBar/UserInfo.js

frontend/src/components/SideBar/index.js

frontend/src/pages/Main/Header.js

frontend/src/pages/Main/index.js

frontend/src/pages/UEInfo/index.js

frontend/src/pages/UEInfoDetail/index.js

frontend/src/util/UEInfoApiHelper.js

frontend/yarn.lock

public/asset-manifest.json

public/index.html

public/service-worker.js

public/static/js/main.2d51e481.js

public/static/js/main.2d51e481.js.map

public/static/js/main.379c4257.js