fix: compile error error: could not convert xx from (#136)

Co-authored-by: arrowbowang <arrowbowang@tencent.com>

Author: mikewhb

src/lance_scan.cpp

@@ -2190,7 +2190,7 @@ LanceExecPushdown(ClientContext &context, Optimizer &optimizer,
         agg_op.group_index, agg_op.aggregate_index, agg_op.groups.size(),
         expected_types, std::move(exec_get));
     exec->SetEstimatedCardinality(estimated_cardinality);
-    return exec;
+    return std::move(exec);
   };
 
   if (op->type == LogicalOperatorType::LOGICAL_ORDER_BY) {

src/lance_storage.cpp

@@ -1147,7 +1147,7 @@ class LanceDuckCatalog final : public DuckCatalog {
                               state->open_path + LanceFormatErrorSuffix());
           }
 
-          return state;
+          return std::move(state);
         }
 
         struct LocalState final : public LocalSinkState {};