[BI-2823] Remove sub entity level name from level relationships in sub entity dataset creation

[davedrp]

Description

BI-2823 Remove sub entity level name from level relationships in sub entity dataset creation

CHANGES
The only change is the removal of the sub entity element from the level relationships element.

Dependencies

bi-web: develop

Testing

GIVEN: an experiment with a sub-entity has been created (and thus sent to the BrAPI server)
THEN: Inspect the JSON data sent to and stored in the BrAPI server.

1. Using an HTTP POST to http://localhost:8083/brapi/v2/search/observationunits
   a. NOTE: here port 8083 was used. Use whatever port the BrAPI server is listening on.
2. BODY

{
"externalReferenceIds": [
"2f0ae898-697c-464c-95ea-0e918cde117d"
]
}

a. NOTE: here the external Reference 2f0ae898-697c-464c-95ea-0e918cde117d was used. Use a sub-entity ObsUnitID from the experiment.

Checklist:

• I have performed a self-review of my own code
• I have tested my code and ensured it meets the acceptance criteria of the story
• I have create/modified unit and/or integration tests to cover this change or tests are not applicable
• I have commented my code, particularly in hard-to-understand areas
• I have either updated the source of truth or arranged for update with product owner if needed https://breedinginsight.atlassian.net/wiki/spaces/BI/pages/1559953409/Source+of+Truth