DolphinQt: Move GraphicsModListWidget::ClearLayoutRecursively() to QtUtils.

Source/Core/DolphinQt/QtUtils/ClearLayoutRecursively.cpp

@@ -0,0 +1,33 @@
+// Copyright 2023 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "DolphinQt/QtUtils/ClearLayoutRecursively.h"
+
+#include <QLayout>
+#include <QLayoutItem>
+#include <QWidget>
+
+void ClearLayoutRecursively(QLayout* layout)
+{
+  while (QLayoutItem* child = layout->takeAt(0))
+  {
+    if (child == nullptr)
+      continue;
+
+    if (child->widget())
+    {
+      layout->removeWidget(child->widget());
+      delete child->widget();
+    }
+    else if (child->layout())
+    {
+      ClearLayoutRecursively(child->layout());
+      layout->removeItem(child);
+    }
+    else
+    {
+      layout->removeItem(child);
+    }
+    delete child;
+  }
+}