Fix for coded concept broken with Most Recent Observation on dashboard TRUNK-4131

@wluyima you mean that if there is no valid answer, then fail with a message? 

In UI, we are suggesting available answers where user will select the one of the answer. 

If the set valueCoded is not set, the observation validator will reject this with the message mentioned in the attached screenshot to the ticket. :).

May be I didn't got your point.