Remove unused dependencies

[MaxFrank13]

There are a handful of package dependencies that appear to be unused by the code in this repository. Some of these just need to be moved to devDependencies while others are not direct requirements and can at least be removed from the package.json. For example, the history package is used by frontend-platform, but not frontend-app-learner-dashboard. So when it's removed from Learner Dashboard package.json, it will only appear in package-lock under frontend-platform, but won't be a direct dependency for Learner Dashboard.

The below listed dependencies were chosen based on a simple search through frontend-app-learner-dashboard to see if they were utilized. Any packages that were not imported from or did not appear to be used in some other way are included in the list.

To assess for removal:

• @redux-beacon/segment
• @testing-library/user-event
• dompurify
• email-prop-type
• file-saver
• filesize
• history
• html-react-parser
• react-pdf
• redux-beacon
• universal-cookie
• whatwg-fetch

To move to devDependencies:

• jest
• jest-environment-jsdom
• jest-when

[jciasenza]

I can take this issue @arbrandes

[jciasenza]

i have made PR #495

[MaxFrank13]

Thanks @jciasenza!