Increment reference count when restoring reference

Otherwise the count will be wrong after an out of memory failure in
reinterpretAsFormat.

Fixes: QTBUG-98377
Change-Id: Ice51d47a6db9277126a5c7337e14aaf5ddee3a10
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit 1a8b7eb1d4f27e74621ee94c01dbeda3afd302c7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/gui/image/qimage.cpp

@@ -2332,6 +2332,7 @@ bool QImage::reinterpretAsFormat(Format format)
         // In case detach() ran out of memory
         if (!d) {
             d = oldD;
+            d->ref.ref();
             return false;
         }
     }