**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.
airflow/providers/amazon/aws/operators/ecs.py
'taskDefinition': self.task_definition,
            'overrides': self.overrides,
            'startedBy': self.owner,
        }
        if self.launch_type:
            run_opts['launchType'] = self.launch_type
            if self.launch_type == 'FARGATE':
                run_opts['platformVersion'] = self.platform_version
        if self.group is not None:
            run_opts['group'] = self.group
        if self.placement_constraints is not None:
            run_opts['placementConstraints'] = self.placement_constraints
        if self.placement_strategy is not None:
            run_opts['placementStrategy'] = self.placement_strategy
        if self.network_configuration is not None:
            run_opts['networkConfiguration'] = self.network_configuration
        if self.tags is not None:
            run_opts['tags'] = [{'key': k, 'value': v} for (k, v) in self.tags.items()]
        if self.propagate_tags is not None:
            run_opts['propagateTags'] = self.propagate_tags
        response = self.client.run_task(**run_opts)
        failures = response['failures']
        if len(failures) > 0:
            raise AirflowException(response)
        self.log.info('ECS Task started: %s', response)
        self.arn = response['tasks'][0]['taskArn']
        self._wait_for_task_ended()
        self._check_success_task()
        self.log.info('ECS Task has been successfully executed: %s', response)
    def _wait_for_task_ended(self) -> None: