[post-migration] test review

[chalmerlowe]

Summary of the issue

During the migration certain issues arose with ensuring the presubmit tests passed. Review the libraries to confirm whether tests marked skip (i.e. due to environmental issues OR dependency version issues) should be updated OR left marked as skip.

python-bigquery
See this commit from #16008 as an example: 7e206e5

Specifically the 7 test marked as skipped here:

........................................................................ [ 37%]
.................................ss...........sssss..................... [ 75%]
..............................................                           [100%]
183 passed, 7 skipped in 350.52s (0:05:50)

sqlalchemy-bigquery
Double check the extra test skipped in #16046 via this commit: 05d45fc

We may want to audit skipped tests in all packages as well