Migrate NULL Location Behaviours To Required

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LocationBehaviour == NULL and LocationBehaviour == Required are being treated in the same way for validation (see here).

We need to check if they are being treated the same in all cases, and if so, a Liquibase changeset should be created that migrates all the NULL values to Required.

The liquibase changeset will go in liquibase-update-to-latest.xml
After this is done, the PatientIdentifierValidator should stop considering null or blank as required