[Core API] Enforce feature access

A bug in our Core API server was letting traffic to some endpoints to go through despite the feature not being accessible to their plan.

Endpoints affected are:

• GET /exports
• GET /exports/:export_id
• POST /exports
• POST /teams/:team_id/exports
• GET /analytics
• GET /teams/:team_id/analytics

Those endpoints will now properly enforce access to the Front Analytics.