fix(ui): drop whatwg-fetch import as it's included in react-app-polyfill

ui/package.json

@@ -50,8 +50,7 @@
     "react-tippy": "1.2.3",
     "react-transition-group": "4.0.0",
     "react-truncate": "2.4.0",
-    "semver": "6.0.0",
-    "whatwg-fetch": "3.0.0"
+    "semver": "6.0.0"
   },
   "scripts": {
     "start": "NODE_ENV=dev REACT_APP_BACKEND_URI=http://localhost:8080 react-scripts start",

ui/src/index.js

@@ -2,9 +2,6 @@
 // https://github.com/facebook/create-react-app/blob/master/packages/react-app-polyfill/README.md
 import "react-app-polyfill/stable";
 
-// fetch() polyfill for IE and some mobile browsers
-import "whatwg-fetch";
-
 import React from "react";
 import ReactDOM from "react-dom";