Issue Summary

This is reproducible on Data Center: (yes) 

When making a REST call and the Person ID is specified, the Person is created which leads to confusion that this endpoint can assign an existing Person with a team. 400 error code should be returned instead. 

Steps to Reproduce

1. Make a call to

POST {{base_url}}/rest/teams-api/latest/resource
Body:
{
  "teamId": 8,
  "person": {
      "id": 123
      "jiraUser": {
      "jiraUserId": "any existing user"
    }
  }
} 

Expected Results

400 HTTP error code

Actual Results

Persona is created and ID is not taken into account.

Workaround

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