Fix appearance of items without icons in wxDataViewCtrl in wxOSX/Cocoa.

We need to set the cell image to none explicitly if the item doesn't have any,
otherwise the image for the previous cell would be reused.

Closes #14112.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70941 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/cocoa/dataview.mm

@@ -2995,6 +2995,8 @@ bool wxDataViewIconTextRenderer::MacRender()
         iconText << GetValue();
         if (iconText.GetIcon().IsOk())
             [cell setImage:[[wxBitmap(iconText.GetIcon()).GetNSImage() retain] autorelease]];
+        else
+            [cell setImage:nil];
         [cell setStringValue:[[wxCFStringRef(iconText.GetText()).AsNSString() retain] autorelease]];
         return true;
     }