Test for existence of PURL config makes too many requests

[jamesaoverton]

This test is failing with an HTTP 429 Too Many Reqeusts error:

https://github.com/OBOFoundry/OBOFoundry.github.io/actions/runs/14736689406/job/41364454604#step:5:54

Since the code is old, and it only started failing now, I expect it's a transient error. But this test_has_purl_config() function is very inefficient: https://github.com/OBOFoundry/OBOFoundry.github.io/blob/master/tests/test_integrity.py#L217. There has to be a better way to do this check without 200+ HTTP requests.

[jsstevenson]

👍 I think I'd like to see (at least) two changes

1. we're basically testing for the existence of several specifically-named files in a subdirectory in the git tree. This could probably be accomplished by a single GitHub API call: https://stackoverflow.com/a/61656698

2. rather than failing as soon as a single discrepancy is encountered, it'd be more helpful to get a complete list of failures. IE collect a list of missing files and fail if it is of len > 0

[deepakunni3]

Resolved via #2715