We often need the logical bitmap size when using it in size computations
involving window size, so add a function returning it directly to
wxBitmapBundle, similarly to wxBitmap::GetLogicalSize(), to avoid using
FromPhys() everywhere.
Also rename the existing wxBitmapBundle::GetPreferredSizeFor() to
GetPreferredBitmapSizeFor() to make it more clear that this is similar
to wxBitmap::GetSize() and so returns the size in physical units.
Closes#22056.
b2629a97e5