### Description

I want to add support of a separate AWS connection for DynamoDB in `DynamoDBToS3Operator` in `apache-airflow-providers-amazon` via `aws_dynamodb_conn_id` constructor argument.



### Use case/motivation

Sometimes DynamoDB tables and S3 buckets live in different AWS accounts so to access both resources you need to assume a role in another account from one of them.
That role can be specified in AWS connection, thus we need to support two of them in this operator.

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] 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)

"""
    Replicates records from a DynamoDB table to S3.
    It scans a DynamoDB table and writes the received records to a file
    on the local filesystem. It flushes the file to S3 once the file size
    exceeds the file size limit specified by the user.
    Users can also specify a filtering criteria using dynamodb_scan_kwargs
    to only replicate records that satisfy the criteria.
    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/transfer:DynamoDBToS3Operator`
    :param dynamodb_table_name: Dynamodb table to replicate data from
    :param s3_bucket_name: S3 bucket to replicate data to
    :param file_size: Flush file to s3 if file size >= file_size
    :param dynamodb_scan_kwargs: kwargs pass to <https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html#DynamoDB.Table.scan>
    :param s3_key_prefix: Prefix of s3 object key
    :param process_func: How we transforms a dynamodb item to bytes. By default we dump the json
    :param aws_conn_id: The Airflow connection used for AWS credentials.
        If this is None or empty then the default boto3 behaviour is used. If
        running Airflow in a distributed manner and aws_conn_id is None or
        empty, then default boto3 configuration would be used (and must be
        maintained on each worker node).