### Apache Airflow Provider(s)

amazon

### Versions of Apache Airflow Providers

apache-airflow-providers-amazon==7.1.0

### Apache Airflow version

2.5.1

### Operating System

Ubuntu 18.04

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### What happened

When looking at logs in the UI for a running task when using remote s3 logging, the logs for the task are only uploaded to s3 after the task has completed. The the `S3TaskHandler` falls back to the local logs stored on the worker in that case (by falling back to the `FileTaskHandler` behavior) and prepends the line `*** Falling back to local log` to those logs.

This is mostly fine, but for the new log streaming behavior, this means that `*** Falling back to local log` is returned from `/get_logs_with_metadata` on each call, even if there are no new logs.

### What you think should happen instead

I'd expect the falling back message only to be included in calls with no `log_pos` in the metadata or with a `log_pos` of `0`.

### How to reproduce

Start a task with `logging.remote_logging` set to `True` and `logging.remote_base_log_folder` set to `s3://something` and watch the logs while the task is running. You'll see `*** Falling back to local log` printed every few seconds.

### Anything else

_No response_

### Are you willing to submit 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)

worker_log_rel_path = self._render_filename(ti, try_number)
        logs = []
        messages = []
        bucket, prefix = self.hook.parse_s3_url(s3url=os.path.join(self.remote_base, worker_log_rel_path))
        keys = self.hook.list_keys(bucket_name=bucket, prefix=prefix)
        if keys:
            keys = [f"s3://{bucket}/{key}" for key in keys]
            messages.extend(["Found logs in s3:", *[f"  * {x}" for x in sorted(keys)]])
            for key in sorted(keys):
                logs.append(self.s3_read(key, return_error=True))
        else:
            messages.append(f"No logs found on s3 for ti={ti}")
        return messages, logs
    def _read(self, ti, try_number, metadata=None):