Enable daily cron for search engine population and make delete ops non-blocking

[mishig25]

Summary

• Enable cron schedule in populate_search_engine.yml so the search engine is populated daily at 07:05 UTC (was commented out).
• Remove wait_for_task_completion wrapper from Meilisearch delete functions (delete_embedding_db, clear_embedding_db, delete_documents_from_db) so they fire-and-forget instead of blocking until the task finishes.

Test plan

• Verify the cron job triggers on schedule (or trigger manually via workflow_dispatch)
• Confirm delete operations still execute correctly without waiting for task completion

Made with Cursor