Client: Fix handling of Qt::BlankCursor

The cursor may not be properly set when a window has Qt::BlankCursor and
it's shown. In that case, the cursor surface may not be present and
wl_pointer.set_cursor won't be called.

On the other hand, wl_pointer.set_cursor must be always called when
wl_pointer.enter is received.

Pick-to: 6.5
Change-Id: I8540e7a02df1579b3380a1a1d4cfab42c1ab3104
Reviewed-by: David Edmundson <davidedmundson@kde.org>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/platforms/wayland/qwaylandinputdevice.cpp

@@ -285,8 +285,7 @@ void QWaylandInputDevice::Pointer::updateCursor()
     auto shape = seat()->mCursor.shape;
 
     if (shape == Qt::BlankCursor) {
-        if (mCursor.surface)
-            mCursor.surface->hide();
+        getOrCreateCursorSurface()->hide();
         return;
     }