ci: add license compliance check

[wochinge]

Related Issues

• https://github.com/deepset-ai/haystack-hub-api/issues/1271

Proposed Changes:

• check license compliance on regular checks as well as PRs (only prod dependencies)
• run license checks on schedule every day at midnight (if it fails it will send a Slack notification)

How did you test it?

Notes for the reviewer

Checklist

• [x] I have read the contributors guidelines and the code of conduct
• [x] I have updated the related issue with new insights and changes
• [ ] I added tests that demonstrate the correct behavior of the change
• [x] I've used the conventional commit convention for my PR title
• [x] I documented my code
• [x] I ran pre-commit hooks and fixed any issue