This PR removes the 'view_chat_history' experiment which hid the teacher view of student chat history for aichat levels behind an experiment flag which was added by #59981.

Implementing the teacher view of student chat history was a multi-PR process (including the refactoring of how we log chat messages) and includes the following:

• Part 1 - View Aichat student chat history: teacher view student history tabs/toggle #59981
• Add AichatEvents table #60052
• [Aichat] Add ChatEvent type #60053
• Add aichat logging controller action #60081
• [Aichat] Log chat events on the frontend #60110
• Update aichat_controller tests / remove logging to AichatSessions #60132
• Add ChatEventLogger unit tests #60191
• Add Aichat controller action to fetch student chat history #60256
• [Aichat] Fetch student chat history and display in workspace #60322
• [Aichat] Teacher view of student chat history - UI updates #60483

Here's a screencast video of a teacher user on production with the experiment flag 'view_chat_history' on. The teacher has 2 students in a section and can view their student chat history on two different levels.

Links

Testing story

Deployment strategy

Follow-up work

Privacy

Security

Caching

PR Checklist:

• Tests provide adequate coverage
• Privacy and Security impacts have been assessed
• Code is well-commented
• New features are translatable or updates will not break translations
• Relevant documentation has been added or updated
• User impact is well-understood and desirable
• Pull Request is labeled appropriately
• Follow-up work items (including potential tech debt) are tracked and linked