**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
"""
    Adds provider packages as requirements to extra. This is used to add provider packages as requirements
    to the "bulk" kind of extras. Those bulk extras do not have the detailed 'extra' requirements as
    initial values, so instead of replacing them (see previous function) we can extend them.
    :param extra: Name of the extra to add providers to
    :param providers: list of provider ids
    """
    EXTRAS_REQUIREMENTS[extra].extend(
        [get_provider_package_from_package_id(package_name) for package_name in providers]
    )
def add_all_provider_packages() -> None:
    """
    In case of regular installation (providers installed from packages), we should add extra dependencies to
    Airflow - to get the providers automatically installed when those extras are installed.
    For providers installed from sources we skip that step. That helps to test and install airflow with
    all packages in CI - for example when new providers are added, otherwise the installation would fail
    as the new provider is not yet in PyPI.
    """
    for provider in ALL_PROVIDERS:
        replace_extra_requirement_with_provider_packages(provider, [provider])
    add_provider_packages_to_extra_requirements("all", ALL_PROVIDERS)
    add_provider_packages_to_extra_requirements("devel_ci", ALL_PROVIDERS)
    add_provider_packages_to_extra_requirements("devel_all", ALL_PROVIDERS)
    add_provider_packages_to_extra_requirements("all_dbs", ALL_DB_PROVIDERS)
    add_provider_packages_to_extra_requirements(
        "devel_hadoop", ["apache.hdfs", "apache.hive", "presto", "trino"]
    )
    add_all_deprecated_provider_packages()
class Develop(develop_orig):