build(ci): rm unneeded call to get_api_key in test (#2199)
Follow-up PR to
[https://github.com/Unstructured-IO/unstructured/pull/2195](https://github.com/Unstructured-IO/unstructured/pull/2195).
Removes unnecessary calls to `get_api_key()`. That helper function is
supposed to only be used for tests decorated by
@pytest.mark.skipif(skip_outside_ci, reason="Skipping test run outside
of CI") (which are skipped because those tests are partitioning pdf/jpg
files).
These tests are partitioning emails and rely on the MockResponse at the
top of the file, so they don't need to call `get_api_key()` and it can
simply be removed from them.
