Cannot save multiple identifiers values

If a patient has multiple identifiers, it is very likely that the registrationapp module would not save all identifiers values entered in the UI.

Steps to reproduce:

1. Select patient with multiple identifiers
2. Navigate to patient registration summary
3. Click on the Identifiers edit section
4. Enter a new value for one of the identifier
5. Click Save
6. On the Registration Summary page the old value is still displayed