feat: add grouped Waffle flags for Snowflake rollout

[santhosh-apphelix-2u]

Summary

• Keep insights_snowflake_enabled as the master rollout switch.
• Add group-level Waffle flags for enrollment, course summaries, engagement, and performance APIs.
• Route traffic to Snowflake only when both the global flag and the matching group flag are enabled.
• Keep Aurora as the default path when the required flags are disabled.
• Preserve the existing course activity flag while ensuring it is also controlled by the global flag.
• Update the affected views and tests.

Rollout behavior

The global flag must be enabled before any Snowflake group can be activated. Each API group can then be enabled independently for controlled rollout and easier rollback.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
analytics_data_api/insights_snowflake
toggles.py
analytics_data_api/tests
test_insights_snowflake.py
analytics_data_api/v0/tests/views
test_course_summaries.py
test_courses.py
test_problems.py
test_programs.py
test_videos.py
analytics_data_api/v0/views
course_summaries.py					262
courses.py
problems.py
programs.py					76
videos.py
Project Total

This report was generated by python-coverage-comment-action