[testing] Test webhook on deployed infrastructure

[davidcavazos]

Currently the tests are running locally in pytest.

There should be an additional test that deploys the webhook into Cloud Functions along with the Eventarc trigger, and it should simply upload a document and wait for a successful processing. This test would fail if a code change or dependency upgrade requires more memory in the Cloud Function deployment.

The existing "local" test is still useful to get logs for debugging.