[CI][Python] python_test_emscripten fails with missing PARQUET_TEST_DATA environment variable

[raulcd]

Describe the bug, including details regarding any error messages, version, and platform.

The test-conda-python-emscripten is failing with the following error:

    @pytest.fixture(scope='module')
    def parquet_test_datadir():
        result = os.environ.get('PARQUET_TEST_DATA')
        if not result:
>           raise RuntimeError('Please point the PARQUET_TEST_DATA environment '
                               'variable to the test data directory')
E           RuntimeError: Please point the PARQUET_TEST_DATA environment variable to the test data directory

This has been failing since this check was introduced in: #41580

Component(s)

Continuous Integration, Python

[kou]

We already have an issue for this: #43868