Fix Upload Items (#682)

* Fix Upload Items

* Remove debugger

* Switch to bulk APIs

* Address TODO

Co-authored-by: Jordi Bunster <jbunster@microsoft.com>

jest.config.js

@@ -69,7 +69,6 @@ module.exports = {
   moduleNameMapper: {
     "^.*[.](svg|png|gif|less|css)$": "<rootDir>/mockModule",
     "@nteract/stateful-components/(.*)$": "<rootDir>/mockModule",
-    "worker-loader": "<rootDir>/mockModule",
     "office-ui-fabric-react/lib/(.*)$": "office-ui-fabric-react/lib-commonjs/$1", // https://github.com/OfficeDev/office-ui-fabric-react/wiki/Fabric-6-Release-Notes
     "^dnd-core$": "dnd-core/dist/cjs",
     "^react-dnd$": "react-dnd/dist/cjs",