[fix](read-uncommitted) Add missing include for UncommittedRowsetRegistry in olap_server

olap_server.cpp calls remove_expired_entries() on UncommittedRowsetRegistry
but only had a forward declaration via storage_engine.h. Add the full header
include to fix the incomplete type error.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dataroaring

be/src/olap/olap_server.cpp

@@ -73,6 +73,7 @@
 #include "olap/tablet_meta_manager.h"
 #include "olap/tablet_schema.h"
 #include "olap/task/engine_publish_version_task.h"
+#include "olap/uncommitted_rowset_registry.h"
 #include "olap/task/index_builder.h"
 #include "runtime/client_cache.h"
 #include "runtime/memory/cache_manager.h"