Allow fetching hass.io panel without auth

[balloob]

Description:

Allow fetching the Hass.io panel from the supervisor without authentication.

Example entry for configuration.yaml (if applicable):

hassio:

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 and @fabaff to be potential reviewers.