Add wxBitmap::GetDIPSize() and use it in wxBitmapBundleImplArt

This fixes the problem with wrong standard bitmaps size when using high
DPI for the main monitor with wxMSW, as GetScaledSize() used here since
31f2892200 (Avoid bitmap scaling in wxArtProvider::GetBitmapBundle(),
2021-12-17) was not the right function to use there.

Closes #19331.

src/common/artprov.cpp

@@ -193,7 +193,7 @@ private:
         // necessary, so use GetScaledSize() and not GetSize().
         const wxBitmap bitmap = wxArtProvider::GetBitmap(id, client);
         if ( bitmap.IsOk() )
-            return bitmap.GetScaledSize();
+            return bitmap.GetDIPSize();
 
         // We really need some default size, so just return this hardcoded
         // value if all else fails -- what else can we do.