[ISSUE #10199] Fix stale write timestamp leads to duplicate transaction commit (#10200)

Author: lizhimins

broker/src/main/java/org/apache/rocketmq/broker/transaction/queue/TransactionalMessageServiceImpl.java

@@ -710,6 +710,7 @@ public long batchSendOpMessage() {
                         // wait for the interval
                         mqContext.getTotalSize().get() < maxSize &&
                                 startTime - mqContext.getLastWriteTimestamp() < interval) {
+                    firstTimestamp = Math.min(firstTimestamp, mqContext.getLastWriteTimestamp());
                     continue;
                 }