/traits call uses a "observationVariableDbId" filter which is not in the returned properties

[guignonv]

The "observationVariableDbId" property, as it can be used as filter, should appear in the returned properties.

[daveneti]

The relationship between observation variable and trait is many to one. A trait can have multiple observation variables associated with it. So it would not be appropreate to return all the observartion variables for a trait in the response. It is better to use the observationVariables endpoint with the trailDbId/traitName/traitPUI filter.