API review: disable copy for new mime converters classes

These classes are polymorphic, so shouldn't be copyable.

Change-Id: I80b6b3de5f5594e00c4011f64846841e3344c152
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
(cherry picked from commit 80cb1426aa325a440993741ba48dd3275f90b2e8)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/gui/platform/darwin/qutimimeconverter.h

@@ -17,6 +17,7 @@ class QMimeData;
 
 class Q_GUI_EXPORT QUtiMimeConverter
 {
+    Q_DISABLE_COPY(QUtiMimeConverter)
 public:
     enum class HandlerScope : uchar
     {

src/gui/platform/windows/qwindowsmimeconverter.h

@@ -20,6 +20,7 @@ class QVariant;
 
 class Q_GUI_EXPORT QWindowsMimeConverter
 {
+    Q_DISABLE_COPY(QWindowsMimeConverter)
 public:
     QWindowsMimeConverter();
     virtual ~QWindowsMimeConverter();