Add new census map UI test

[drewsamnick]

Addressing PR feedback from #20978. No rush on reviewing this.

A bunch of small changes plus I added a test of the new functionality to confirm that after selecting a school from the map dropdown and clicking the info window link that the school id in the form is set correctly.

[drewsamnick]

Trying to figure out why the new test works fine for me but then is failing in circle.

[drewsamnick]

I was finally able to get this new test to pass and it is ready to be reviewed.

In addition to the test there are two other changes that were needed:

1. Add an X-Requested-With header to the school autocomplete fetch call. This was needed to prevent getting a 403 response in the circle environment. The 403 was coming from Rack::Protection::JsonCsrf. That runs after the Rails controller and so the logs showed the controller had successfully handled the request with a 200 status code. Setting the X-Requested-With header causes request.xhr? to return true and thus avoids the 403. Without the header the code falls through to checking referrer(request.env) != request.host. On my dev environment those are both localhost-studio.code.org so the inequality test fails and there is no 403. On circle the referrer is localhost.code.org and the host is localhost-studio.code.org so we get the 403. My best guess for that difference is that the referrer(request.env) call will return the host if there is no HTTP_REFERER in the request. We remove that header and I suspect that it doesn't get removed in circle. If I remove Referer from the list of REMOVED_HEADERS then I can repro the 403 locally.
2. Make the census fusion table id available in non-production environments. We can't test the map functionality without that. Originally I set it only for production to avoid any accidental updates with non-production data. Since it is very unlikely that anyone will run the update script on those environments I relaxed the constraint to set it everywhere other then development. We may eventually want to create separate fusion tables for the different environments.

[breville]

Should we refactor so that this function calls the new one above?

[drewsamnick]

Looks like the more specific step isn't actually in use anywhere so I'm just going to remove it.

[breville]

nit: Choose :)

[drewsamnick]

I chose to fix this typo.