use .get method with default {} for attributes["properties"]

[Gabbytam]

Target was failing on below block for stripe charges where there is a field that was type = object but did not have a properties key.

if cleaned_type == "object":
            field_definitions[name] = build_struct_type(
                attributes["properties"], new_level
            )

Error log:

[info     ]     attributes["properties"], new_level cmd_type=elb consumer=True name=target-s3-parquet producer=False stdio=stderr string_id=target-s3-parquet
[info     ] KeyError: 'properties'

This change resolved the failure.

Ex of failing attribute:

Ex of other type object attribute:

[ndrluis]

@Gabbytam, thank you for your contribution! Could you please add some tests for this fix?