Content Classification Label updates

[Xemdo]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Problem/Feature

Updated mock EventSub and mock API to include Content Classification Label updates.

Description of Changes:

• Added Mock API endpoint /content_classification_labels
• Updated /channels Mock API endpoint to include Content Classification Labels
• Added is_branded_content flag to /channels Mock API endpoint
• Split channel.update EventSub event into 1 and beta (which will be v2 in the future). beta/v2 supports CCL information

Checklist

• My code follows the Contribution Guide
• I have self-reviewed the changes being requested
• I have made comments on pieces of code that may be difficult to understand for other editors
• I have updated the documentation (if applicable)