survey take handles unspecified ref ids #4564

Survey taker will fill in reference ids for answeres when the question
has only one answer even if the answer as a reference identifier.

This is to use helper questions as dependencies, which reqired adding
a reference identiier to the answers.

see https://github.com/NUBIC/ncs_navigator_instruments/commit/8b2075766f4798cb4c24af54d026366b5c301464
address feedback :-( #4564
Merge pull request #281 from NUBIC/4564_partverif_prepopulation

4564 partverif prepopulation