Relax `AttachableImageFormat.init(CLSID)` to allow other CLSIDs

[grynspan]

Consider relaxing AttachableImageFormat.init(CLSID) to allow other CLSIDs/GUIDs, specifically:

• The GUID returned by IWICBitmapCodecInfo::GetContainerFormat()
• Constants such as GUID_ContainerFormatPng (which presumably equal those returned by IWICBitmapCodecInfo::GetContainerFormat()
• CLSIDs for corresponding decoders such as CLSID_WICPngDecoder

See Also: WIC GUIDs and CLSIDs