fix(backend): include agent_output_demo in vector search migration view

Add agentOutputDemoUrl field to StoreAgent view in the vector search
migration to preserve the field added by the merged output video column
migration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

autogpt_platform/backend/migrations/20251204121212_add_vector_search/migration.sql

@@ -54,6 +54,7 @@ SELECT
     sl.slug,
     COALESCE(slv.name, '') AS agent_name,
     slv."videoUrl" AS agent_video,
+    slv."agentOutputDemoUrl" AS agent_output_demo,
     COALESCE(slv."imageUrls", ARRAY[]::text[]) AS agent_image,
     slv."isFeatured" AS featured,
     p.username AS creator_username,