feat(EMS-4015): application submission - xlsx - uk broker address

[ttbarnes]

Introduction ✏️

This PR updates the application submission's XLSX mapping to handle UK broker addresses.

Previously, the XLSX would only render a single FULL_ADDRESS string. Now, UK addresses are supported which contain multiple fields. Therefore we need to map these fields/substrings into a single string.

Resolution ✔️

• Create new mapBrokerAddress helper function.
• Create new mapBrokerAddressBasedInTheUk helper function.
• Update mapBroker to consume mapBrokerAddress.
• Add isEmptyString helper function to the API.
• Update test mocks, types and mocks.