Improve conditional for checking Donation RT Name source field value
Improve conditional for checking Donation RT Name source field value

This change skips the check if the Donation Record Type Name field has
no value, and verifies that the value is a legitimate record type id for
this object before assigning the value as the RecordType Name.

SalesforceFoundation/Cumulus,SalesforceFoundation/Cumulus,SalesforceFoundation/Cumulus,SalesforceFoundation/Cumulus