Remove React-Intl undefined permission translation error filtering

Resolving UIU-488 necessitated the use of FormattedMessage's defaultMessage prop. However, even when you use this prop react-intl throws an error onto the console.

To avoid excessive console spam when viewing users (thousands of errors), we temporarily filtered the error messages reported by React Intl in Root.js using IntlProvider's onError prop.

We will remove this prop after a grace period has passed to allow app devs some time to provide translations for their permission sets. The grace period should expire well before Goldenrod release. We should use May 15 as the date by which to have removed this filtering and addressed this JIRA, since that's the date of the API freeze.