When removing endSprintID field of a Feature through API startSprintID is removed as well

Issue Summary

When removing endSprintID field of a Feature through API PATCH the field startSprintID is removed as well

This is reproducible on Data Center: yes

Steps to Reproduce

1. Create Feature in JA
2. Enable toggle for TargetSprint fields in Admintration > Settings > Details Panel Settings
3. Go to the Feature and update Target Start and Target Completion fields
4. Update to null the endSprintID field on the Feature through API using PATCH.
5. startSprintID will set to null as well.

Expected Results

startSprintID not be allowed to be removed unless endSprintID is also removed (both values must be null or both must be populated, else throw an error)

Actual Results

Users dont know we're automatically removing one of the values of the other is removed

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available