## Description
This PR adds a method on the `Address` class to normalize states in a
`PIIRecord` to the 2-digit USPS code if the provided state is valid. in
order for the normalization to apply when the PIIRecord is constructed
or initialized via `schemas.PIIRecord(**val)` as it is in
`fhir_record_to_pii_record`, I needed to add the method as a
`field_validator` on the Address class. We may want to update the other
normalization functions, e.g., `phone_number` and `email` to ensure that
the same normalization occurs for those fields as well.

While working on this PR, I realized that we may also want to update the
`field_validators` that are part of `PIIRecord`. For example,
`parse_birth_date` returns a datetime object when we run
`.model_construct` (see tests in `TestPIIRecord`) but returns the date
as a string when we `schemas.PIIRecord(**val)` (see tests in
`test_fhir_record_to_pii_record`. I propose we ensure that the
normalization and validation are consistent for handling a PIIRecord
with incoming FHIR data.

I also changed the way that we initialize the PIIRecord in
`model_construct`. I'm not clear how the old approach worked since it
seemed to be calling itself, but with the new approach we are now able
to apply both field validators on the PIIRecord and within the fields,
e.g., the new validator I added to Address.

## Related Issues
Fixes #202 

## Additional Notes


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