Fix downloader_download_failed event not firing for HTTP response errors

[sfjes]

Description:

Fix downloader_download_failed event not firing for HTTP response errors

The Downloader component documentation at https://www.home-assistant.io/components/downloader/ says:

In case download failed another event ‘downloader_download_failed’ is emitted to indicate that the download did not complete successfully.

However currently the event is only fired if there's a ConnectionError exception, and not if the download fails due to a non-200 HTTP response code. Only a warning is logged. According to the docs, this case should also fire a downloader_download_failed event. This PR adds that event.

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the [development checklist][dev-checklist]

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[sfjes]

I associated the commit email with my GitHub user. Let me know if additional steps are necessary.

[balloob]

Thanks!