fix: not keep wal log vnodeCommit'ed for single replica db

source/libs/sync/src/syncMain.c

@@ -292,8 +292,6 @@ int32_t syncBeginSnapshot(int64_t rid, int64_t lastApplyIndex) {
     goto _DEL_WAL;
 
   } else {
-    lastApplyIndex -= SYNC_VNODE_LOG_RETENTION;
-
     SyncIndex beginIndex = pSyncNode->pLogStore->syncLogBeginIndex(pSyncNode->pLogStore);
     SyncIndex endIndex = pSyncNode->pLogStore->syncLogEndIndex(pSyncNode->pLogStore);
     bool      isEmpty = pSyncNode->pLogStore->syncLogIsEmpty(pSyncNode->pLogStore);
@@ -308,6 +306,8 @@ int32_t syncBeginSnapshot(int64_t rid, int64_t lastApplyIndex) {
     if (pSyncNode->replicaNum > 1) {
       // multi replicas
 
+      lastApplyIndex -= SYNC_VNODE_LOG_RETENTION;
+
       if (pSyncNode->state == TAOS_SYNC_STATE_LEADER) {
         pSyncNode->minMatchIndex = syncMinMatchIndex(pSyncNode);