Samples tests for `samples/beam` fail with python 3.7 and newer versions of `apache-beam` and `google-cloud-bigtable`

[parthea]

See build log here.

Using apache-beam==2.52.0 and google-cloud-bigtable==2.21.0 samples test fail. Reverting back to apache-beam===2.46.0 and google-cloud-bigtable===2.17.0 for python 3.7 only allows tests to pass.

------------------------------------------------------------
- testing samples/beam
------------------------------------------------------------
nox > Running session py-3.7
nox > Creating virtual environment (virtualenv) using python3.7 in .nox/py-3-7
nox > python -m pip install -r requirements.txt
nox > python -m pip install -r requirements-test.txt
nox > pytest --junitxml=sponge_log.xml
============================= test session starts ==============================
platform linux -- Python 3.7.17, pytest-7.4.3, pluggy-1.2.0
rootdir: /workspace
collected 1 item

hello_world_write_test.py F                                              [100%]

=================================== FAILURES ===================================
____________________________ test_hello_world_write ____________________________

table_id = 'mobile-time-series-3fbd0741-3084-4f'

    def test_hello_world_write(table_id):
        hello_world_write.run(
            [
                "--bigtable-project=%s" % PROJECT,
                "--bigtable-instance=%s" % BIGTABLE_INSTANCE,
                "--bigtable-table=%s" % table_id,
            ]
        )

        client = bigtable.Client(project=PROJECT, admin=True)
        instance = client.instance(BIGTABLE_INSTANCE)
        table = instance.table(table_id)

        rows = table.read_rows()
        count = 0
        for _ in rows:
            count += 1
>       assert count == 2
E       assert 0 == 2

[billyjacobson]

Can the build be reran? This code seems pretty simple, so I wonder if there was just some flakiness?