Investigate transient failure in test_timestream unit test

[EthanBunce]

Describe the bug

Unit tests are transiently failing with similar errors to below. One possible explanation is it is dropping a trailing 0, thus failing the test. This would lead to a failure rate of 10%.

We should investigate this further to improve the unit test reliability.

=================================== FAILURES ===================================
___________________ test_time_unit_precision[MICROSECONDS-6] ___________________
[gw15] linux -- Python 3.9.2 /codebuild/output/src2263616497/src/github.com/aws/aws-sdk-pandas/.venv/bin/python3
timestream_database_and_table = 'tbl_20250616111618312269_386726'
time_unit = 'MICROSECONDS', precision = 6
    @pytest.mark.parametrize(
        "time_unit,precision",
        [(None, 3), ("SECONDS", 1), ("MILLISECONDS", 3), ("MICROSECONDS", 6)],
    )
    def test_time_unit_precision(timestream_database_and_table, time_unit, precision):
        df_write = pd.DataFrame(
            {
                "time": [datetime.now()] * 3,
                "dim0": ["foo", "boo", "bar"],
                "dim1": [1, 2, 3],
                "measure0": ["a", "b", "c"],
                "measure1": [1.0, 2.0, 3.0],
            }
        )
    
        rejected_records = wr.timestream.write(
            df=df_write,
            database=timestream_database_and_table,
            table=timestream_database_and_table,
            time_col="time",
            time_unit=time_unit,
            measure_col=["measure0", "measure1"],
            dimensions_cols=["dim0", "dim1"],
            measure_name="example",
        )
        assert len(rejected_records) == 0
    
        df_query = wr.timestream.query(
            f"""
            SELECT
                *
            FROM "{timestream_database_and_table}"."{timestream_database_and_table}"
            """,
        )
>       assert len(str(df_query["time"][0].timestamp()).split(".")[1]) == precision
E       AssertionError: assert 5 == 6
E        +  where 5 = len('90541')

How to Reproduce

Run the unit tests.

Expected behavior

No response

Your project

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Screenshots

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OS

Windows

Python version

All

AWS SDK for pandas version

All

Additional context

No response