chore: log when export API URL fails

[pauldambra]

Problem

related to #11204

Follows accidental commit to master https://github.com/PostHog/posthog/commit/bcaa4633b45948a41651de7e0fca0e760701a910

We're still getting very unexpected API URL format failures for some CSV export

Changes

logs lots of info about the URL when it fails

How did you test this code?

running developer tests and checking exports locally