Add fallback components to selected part of the UI

[sarathms]

While researching solutions for #1245, I came across react-error-boundary which provides an API to setup fallback UI to mount when the app encounters runtime errors in renders. It doesn't make sense to use it at very granular level like in the below example, but it might be useful to implement at a higher level and provide a graceful way to recover when test results contain unexpected values or expected values are absent. Of course, some UX brainstorming is needed to identify which parts of UI warrant a fallback version.

Stable UI

Fallback component (only contains a simple string here) when any of the 4 values in the columns throw unhandled exceptions.

[hellais]

This may also be relevant to Explorer

[sarathms]

Related issue for explorer: ooni/explorer#516

[hellais]

Superseeded by #2845