Add billing record ua to rules engine example input

[eriksynn]

Updated example csv data in test cases to enable new test for billing period home heat loss data algorithm verification.

[debajyotid2]

@eriksynn It looks like the old type annotation for List in test_examples.py is causing the pytest check to fail. Perhaps replacing it with list would help.

# Then overload NG Billing Input to contain new NG Billing Record Example Input subclass
class NaturalGasBillingExampleInput(NaturalGasBillingInput):
    records: List[NaturalGasBillingRecordExampleInput]

[eriksynn]

@eriksynn It looks like the old type annotation for List in test_examples.py is causing the pytest check to fail. Perhaps replacing it with list would help.

# Then overload NG Billing Input to contain new NG Billing Record Example Input subclass
class NaturalGasBillingExampleInput(NaturalGasBillingInput):
    records: List[NaturalGasBillingRecordExampleInput]

Yes, I made that change just now. I think this PR is now aligned with your previously submitted changes. And I fixed the import formatting that lint was complaining about. The only thing that is still failing is the pyodide.test.ts which I think is not a rules_engine thing.