Fix DD_FLUSH_TO_LOG env var type checking

Author: leandrodamascena

noxfile.py

@@ -80,6 +80,7 @@ def test_with_datadog_as_required_package(session: nox.Session):
         folders=[
             f"{PREFIX_TESTS_FUNCTIONAL}/metrics/datadog/",
         ],
+        extras="datadog,aws-sdk",  # Datadog library requires boto3
     )