**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
"""Forces removal of providers in editable mode."""
    def run(self) -> None:  
        self.announce('Installing in editable mode. Uninstalling provider packages!', level=log.INFO)
        
        
        
        try:
            installed_packages = (
                subprocess.check_output(["python3", "-m", "pip", "freeze"]).decode().splitlines()
            )
            airflow_provider_packages = [
                package_line.split("=")[0]
                for package_line in installed_packages
                if package_line.startswith("apache-airflow-providers")
            ]
            self.announce(f'Uninstalling ${airflow_provider_packages}!', level=log.INFO)
            subprocess.check_call(["python3", "-m", "pip", "uninstall", "--yes", *airflow_provider_packages])
        except subprocess.CalledProcessError as e:
            self.announce(f'Error when uninstalling airflow provider packages: {e}!', level=log.WARN)
        super().run()
class Install(install_orig):