Delivra: Update entity fails if email address not provided

Description

Currently, there is a check to ensure that an email address is provided when inserting an entity. This works fine when creating a new entity but fails when updating it, since email is not required for the update (only MemberID is required for update).
Steps to reproduce

1) Create a form (form 1) with one field, mapped to "EmailAddress".
2) Create another form (form 2) with two fields: one mapped to "FirstName" and the other to "LastName".
3) Add a visitor group with the criteria set to "EmailAddress is not null".
4) Place the two forms on any page of an Alloy site.
5) Personalize form 1 to be visible to the Everyone group.
6) Personalize form 2 to be visible only to the group created in step 3.
7) Submit form 1 and refresh the page. Form 2 is displayed.
8) Submit form 2 and refresh the page.

Expected:
Fields in form 2 are pre-filled with FirstName and LastName.

Actual:
The fields are empty.