**Description**

In similar fashion to https://github.com/apache/airflow/pull/4083, it would be helpful for Airflow to reattach itself to the ECS Task rather than letting another instance to start. However, instead of making this the default behavior, it would be better to use a `reattach` flag.

**Use case / motivation**

Allow Airflow the option to reattach to an existing ECS task when a restart happens, which would avoid having "rogue" tasks.
tests/providers/amazon/aws/operators/test_ecs.py
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import sys
import unittest
from copy import deepcopy
from unittest import mock
from parameterized import parameterized
from airflow.exceptions import AirflowException
from airflow.providers.amazon.aws.operators.ecs import ECSOperator
RESPONSE_WITHOUT_FAILURES = {
    "failures": [],
    "tasks": [
        {
            "containers": [
                {
                    "containerArn":
                        "arn:aws:ecs:us-east-1:012345678910:container/e1ed7aac-d9b2-4315-8726-d2432bf11868",
                    "lastStatus": "PENDING",
                    "name": "wordpress",
                    "taskArn": "arn:aws:ecs:us-east-1:012345678910:task/d8c67b3c-ac87-4ffe-a847-4785bc3a8b55"
                }
            ],
            "desiredStatus": "RUNNING",