**Apache Airflow version**: 2.0.1

**Environment**:

- **Cloud provider or hardware configuration**: AWS

**What happened**:
I have Airflow with Cloudwatch-based remote logging running. I also have `BashOperator` that does, for example, `rsync` with invalid parameters, for example `rsync -av test test`. The output of the `rsync` error is formatted and contains empty line. Once that empty line is logged to the Cloudwatch, i receive an error:
```
2021-04-06 19:29:22,318] /home/airflow/.local/lib/python3.6/site-packages/watchtower/__init__.py:154 WatchtowerWarning: Failed to deliver logs: Parameter validation failed:
Invalid length for parameter logEvents[5].message, value: 0, valid range: 1-inf
[2021-04-06 19:29:22,320] /home/airflow/.local/lib/python3.6/site-packages/watchtower/__init__.py:158 WatchtowerWarning: Failed to deliver logs: None
```

So basically empty lines can't be submitted to the Cloudwatch and as result the whole output of the process doesn't appear in logs.

**What you expected to happen**:

I expect to have an output of the bash command in logs. Empty lines can be skipped or replaced with something.

**How to reproduce it**:

For example: run `BashOperator` with `rsync` command that fails on Airflow with Cloudwatch-based remote logging. It could be any other command that produces empty line in the output.
setup.py
When installing providers from sources we install all namespace packages found below airflow,
        including airflow and provider packages, otherwise defaults from setup.cfg control this.
        The kwargs in setup() call override those that are specified in setup.cfg.
        """
        if os.getenv(INSTALL_PROVIDERS_FROM_SOURCES) == 'true':
            setup_kwargs['packages'] = find_namespace_packages(include=['airflow*'])
    include_provider_namespace_packages_when_installing_from_sources()
    if os.getenv(INSTALL_PROVIDERS_FROM_SOURCES) == 'true':
        print("Installing providers from sources. Skip adding providers as dependencies")
    else:
        add_all_provider_packages()
    write_version()
    setup(
        distclass=AirflowDistribution,
        version=version,
        extras_require=EXTRAS_REQUIREMENTS,
        download_url=('https://archive.apache.org/dist/airflow/' + version),
        cmdclass={
            'extra_clean': CleanCommand,
            'compile_assets': CompileAssets,
            'list_extras': ListExtras,
            'install': Install,  
            'develop': Develop,
        },
        test_suite='setup.airflow_test_suite',
        **setup_kwargs,  
    )
if __name__ == "__main__":
    do_setup()  # co