### Apache Airflow version

Other Airflow 2 version (please specify below)

### What happened

Airflow 2.3.4 (but actual code seems to have same behaviour).

I have mapped task with xcom value.

I want to get xcom value of particular instance or xcom values of all task instances.

I am using standard REST API method /dags/{dag_id}/dagRuns/{dag_run_id}/taskInstances/{task_id}/xcomEntries/{xcom_key}

And it throws an error
`
  File &#34;/home/airflow/.local/lib/python3.9/site-packages/sqlalchemy/orm/query.py&#34;, line 2850, in one_or_none
    return self._iter().one_or_none()
  File &#34;/home/airflow/.local/lib/python3.9/site-packages/sqlalchemy/engine/result.py&#34;, line 1510, in one_or_none
    return self._only_one_row(
  File &#34;/home/airflow/.local/lib/python3.9/site-packages/sqlalchemy/engine/result.py&#34;, line 614, in _only_one_row
    raise exc.MultipleResultsFound(
sqlalchemy.exc.MultipleResultsFound: Multiple rows were found when one or none was required
`

Is it any way of getting xcom of mapped tasks via API?

### What you think should happen instead

_No response_

### How to reproduce

Make dag with mapped task. Return xcom value in every task. Try to get xcom value via API.

### Operating System

ubuntu 20.04

### Versions of Apache Airflow Providers

_No response_

### Deployment

Other

### Deployment details

Standard

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

dag = self.dag
            kwargs = {
                "state": State.RUNNING,
                "start_date": self.start_date,
                "session": self.session,
                **kwargs,
            }
            
            
            if "run_id" not in kwargs and "run_type" not in kwargs:
                kwargs["run_id"] = "test"
            if "run_type" not in kwargs:
                kwargs["run_type"] = DagRunType.from_run_id(kwargs["run_id"])
            if kwargs.get("execution_date") is None:
                if kwargs["run_type"] == DagRunType.MANUAL:
                    kwargs["execution_date"] = self.start_date
                else:
                    kwargs["execution_date"] = dag.next_dagrun_info(None).logical_date
            if "data_interval" not in kwargs:
                logical_date = timezone.coerce_datetime(kwargs["execution_date"])
                if kwargs["run_type"] == DagRunType.MANUAL:
                    data_interval = dag.timetable.infer_manual_data_interval(run_after=logical_date)
                else:
                    data_interval = dag.infer_automated_data_interval(logical_date)
                kwargs["data_interval"] = data_interval
            self.dag_run = dag.create_dagrun(**kwargs)
            for ti in self.dag_run.task_instances:
                ti.refresh_from_task(dag.get_task(ti.task_id))
            return self.dag_run
        def create_dagrun_after(self, dagrun, **kwargs):