[Feature flag] Rollout of: `add_actor_based_user_to_snowplow_tracking` and `add_namespace_and_project_to_snowplow_tracking`

What does this MR do and why?

Both add_namespace_and_project_to_snowplow_tracking and add_actor_based_user_to_snowplow_tracking are enabled for over a week on gitlab.com and proven working correctly, there is no longer need to keep feature flags in the codebase. This MR cleans them up.

Related to: #338670 (closed) and #336665 (closed)

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Related to #336665 (closed)