When our GitHub endpoints return a non-JSON result, show a nice error page.

[noway]

Is your feature request related to a problem? Please describe.
I'm always frustrated when we have an outage, and we're not showing a nice error on the frontend.

Describe the solution you'd like
When outage happens, our GitHub endpoints (healhpointLocations.json, uniqLocations.json, availability/*.json) show an empty resonse. This fails the Fetch library during parsing (const data = await res.json) and we end up spitting out "Unexpected token < in JSON at position 0" error. We should make a nicer error for this case.

Additional context
Can test this by pointing the endpoints to https://google.com or a website which doesn't return JSON.