feat: update react & react-dom to v17 (#514)

* feat: update react & react-dom to v17

* refactor: updated package-lock

* refactor: updated failing tests

* refactor: updated FilesAndUploads test to resolve delay issue

* refactor: updated DiscussionSettings tests

* refactor: downgraded frontend-lib-content-components

* refactor: resolved lint issue

* refactor: bumped frontend-lib-content-components version

* refactor: updated CollapsibleStateWithAction test suit

* refactor: update FilesAndUploads test