[qs] reduce max txn per batch

Author: Zekun Li

config/src/config/quorum_store_config.rs

@@ -10,7 +10,7 @@ use serde::{Deserialize, Serialize};
 use std::time::Duration;
 
 pub const BATCH_PADDING_BYTES: usize = 160;
-pub const DEFEAULT_MAX_BATCH_TXNS: usize = 100;
+pub const DEFEAULT_MAX_BATCH_TXNS: usize = 50;
 const DEFAULT_MAX_NUM_BATCHES: usize = 10;
 
 #[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]