issue: #44369
woodpecker related[ issue:
#59](https://github.com/zilliztech/woodpecker/issues/59)
Refactor the WAL retention logic in Milvus StreamingNode:
- Remove the simple sampling-based truncation mechanism.
- After flush, WAL data is directly truncated.
- The retention control is now delegated to the underlying message queue
(MQ) implementation.
Signed-off-by: tinswzy <zhenyuan.wei@zilliz.com>
1427825133