Unable to capture UNKNOWN HispanicLatinoEthnicity

Summary of outcomes for Data Standard 2.1

• Problem Addressed: The boolean field HispanicLatinoEthnicity included in the Student and Staff domain entities does not support the case in which HispanicLatinoEthnicity is not known.
• High-level Reasoning: HispanicLatinoEthnicity is boolean and required in both domain entities. In cases where the HispanicLatinoEthnicity is unknown, it must be recorded as false. It is therefore impossible to differentiate between when it is known that HispanicLatinoEthnicity is truly false or simply unknown.
• Changes Made: Updated Student.HispanicLatinoEthnicity and Staff.HispanicLatinoEthnicity to be optional. A NULL value now suggests that the person's HispanicLatinoEthnicity is unkown, whereas a false value indicates that the person is not Hispanic/Latino.

Original ticket description follows:

Issue pointed out by Harmony:
HispanicLatinoEthnicity is a required element for Student and Staff.

There are points in time when this information has not been collected / reported.
Need HispanicLatinoEthnicity to be NULL during that time frame.
As a work around, Harmony will have to submit FALSE during the "not reported / collected" time frame.
For Harmony, they need to be able to discern between "Not Reported" vs "was reported as Non Hispanic"

Note: first preference was to submit "UNKNOWN" rather than assuming NULL means same but since is a bit field, will accept NULL as solution;