DAP: Fix auto copy

Coverity-Id: 1568078
Change-Id: I915f947dee43b78248dcb29fe375954b43344920
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>

src/plugins/debugger/dap/dapengine.cpp

@@ -812,7 +812,7 @@ void DapEngine::refreshLocals(const QJsonArray &variables)
     if (currentItem && currentItem->iname.startsWith("watch"))
         currentItem->removeChildren();
 
-    for (auto variable : variables) {
+    for (const QJsonValueConstRef &variable : variables) {
         WatchItem *item = new WatchItem;
         const QString name = variable.toObject().value("name").toString();