Consider using a CSP error reporting service

[toolness]

We realized fairly late that #1451 was occurring. While this wasn't that big a deal since FullStory is just an analytics service, it'd be unfortunate if a third-party service we relied on more--like the NYC GeoSearch API--started failing for similar reasons.

It might be useful to use a service like Sentry's Security Policy Reporting so we're alerted to these kinds of things sooner rather than later.