**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
"""The setuptools.Distribution subclass with Airflow specific behaviour"""
    def __init__(self, attrs=None):
        super().__init__(attrs)
        self.install_requires = None
    def parse_config_files(self, *args, **kwargs) -> None:
        """
        Ensure that when we have been asked to install providers from sources
        that we don't *also* try to install those providers from PyPI.
        Also we should make sure that in this case we copy provider.yaml files so that
        Providers manager can find package information.
        """
        super().parse_config_files(*args, **kwargs)
        if os.getenv(INSTALL_PROVIDERS_FROM_SOURCES) == 'true':
            self.install_requires = [
                req for req in self.install_requires if not req.startswith('apache-airflow-providers-')
            ]
            provider_yaml_files = glob.glob("airflow/providers/**/provider.yaml", recursive=True)
            for provider_yaml_file in provider_yaml_files:
                provider_relative_path = relpath(provider_yaml_file, os.path.join(my_dir, "airflow"))
                self.package_data['airflow'].append(provider_relative_path)
        else:
            self.install_requires.extend(
                [get_provider_package_from_package_id(package_id) for package_id in PREINSTALLED_PROVIDERS]
            )
def replace_extra_requirement_with_provider_packages(extra: str, providers: List[str]) -> None: