removed index on error.aid as previous PR added it

Author: Jamesbarford

database/src/pool/postgres.rs

@@ -415,12 +415,6 @@ static MIGRATIONS: &[&str] = &[
     r#"
     CREATE INDEX IF NOT EXISTS benchmark_request_completed_idx ON benchmark_request(completed_at);
     "#,
-    // Artifacts table grows massively and we do a join on artifacts.id = error.aid.
-    // Thus error.aid needs an index to filter errors for an artifact without
-    // a full table scan
-    r#"
-    CREATE INDEX IF NOT EXISTS error_aid_idx ON error(aid);
-    "#,
 ];
 
 #[async_trait::async_trait]