Fix automation failing to setup if no automations specified

[balloob]

Description:

The automation component would fail to setup if no automations specified. Since the introduction of the automation editor we enable the automation editor in the default config, causing that to break out of the box. This fixes it by allowing the automation editor to setup correctly when there are no automations.

Example entry for configuration.yaml (if applicable):

automation:

Checklist:

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[mention-bot]

@balloob, thanks for your PR! By analyzing the history of the files in this pull request, we identified @pvizeli, @fabaff and @philipbl to be potential reviewers.