Missing street address on a gift added to event registration

For GiveCampus integrations and API.

The Gifts API derives address line 1 from the gift contribution's stored mailing address. The optional-event-gift creation path copies registrant identity/affiliations and retrieves a postal code from the payment method, but does not populate the contribution's street mailing address. Therefore an event registration having address answers is not proof those answers will appear as the gift's API line 1. Have support compare the actual registration and contribution; do not invent an address or assume the API dropped a populated street field. Other checkout paths can differ.