[KVConnector] Enable get_block_ids_with_load_errors() in LMCache connector

vllm/distributed/kv_transfer/kv_connector/v1/lmcache_connector.py

@@ -128,6 +128,21 @@ def get_finished(
         """
         return self._lmcache_engine.get_finished(finished_req_ids)
 
+    def get_block_ids_with_load_errors(self) -> set[int]:
+        """
+        Get the set of block IDs that failed to load.
+
+        Returns:
+            Set of block IDs that encountered load errors.
+            Empty set if no load errors occurred.
+        """
+        method = getattr(self._lmcache_engine, "get_block_ids_with_load_errors", None)
+        if callable(method):
+            return method()
+        else:
+            # Fallback for older versions that don't support this method
+            return set()
+
     # ==============================
     # Scheduler-side methods
     # ==============================