'test_new_bucket_created_w_unspecified_pap' systest flakes

[tseaver]

From this Kokoro failure:

__________________ test_new_bucket_created_w_unspecified_pap ___________________

storage_client = <google.cloud.storage.client.Client object at 0x7fca9111bc10>
buckets_to_delete = [<Bucket: new-w-pap-unspecified-1632759084261>]
blobs_to_delete = []

    def test_new_bucket_created_w_unspecified_pap(
        storage_client, buckets_to_delete, blobs_to_delete,
    ):
        from google.cloud.storage import constants

        bucket_name = _helpers.unique_name("new-w-pap-unspecified")
        bucket = storage_client.bucket(bucket_name)
        bucket.iam_configuration.uniform_bucket_level_access_enabled = True
        bucket.create()
        buckets_to_delete.append(bucket)

>       assert (
            bucket.iam_configuration.public_access_prevention
            == constants.PUBLIC_ACCESS_PREVENTION_UNSPECIFIED
        )
E       AssertionError: assert 'inherited' == 'unspecified'
E         - unspecified
E         + inherited

tests/system/test_bucket.py:820: AssertionError

[unforced]

Hm, seems perhaps this is linked to #597
We are currently changing unspecified to inherited.

[cojenco]

^If needed, we can submit a PR to temporarily skip this test.