KRACOEUS-8338:fixes issue with custom data not being passed to instituti...

...onal proposals
I believe the JPA changes broke this.  InstitutionalProposalServiceImpl tries to get the the custom data values from the document.customAttributeDocuments which is a transient field.  The actual custom data values are persisted on document.customDataList.  I believe previously it was working because the SaveCustomDataEvent would set the value of the custom attribute in the customAttributeDocument, and that value wouldn't be cleared like it is with JPA.