yuzu/wait_tree: Pass QString by value and std::move in the initializer list for WaitTreeText

Just a trivial modernization that potentially avoids copying strings in certain scenarios.

src/yuzu/debugger/wait_tree.h

@@ -52,7 +52,7 @@ private:
 class WaitTreeText : public WaitTreeItem {
     Q_OBJECT
 public:
-    explicit WaitTreeText(const QString& text);
+    explicit WaitTreeText(QString text);
     ~WaitTreeText() override;
 
     QString GetText() const override;