Check for repeatable question group observations being array and not object

There was one observation in Lahi which was an object. This causes the ETL job to fail. ETL failure is downstream and it can result in bad data getting created that needs to be handled via support. We should have a check and correction of data when such data is being pushed to the server.

The issue names no files, tests, or entry points. Start by tracing where question group observations are accepted or pushed to the server and how the ETL payload is formed. Done means object-shaped repeatable question group observations are detected and corrected before they can cause ETL failure or bad downstream data.

Written by the indexing model from the issue text.