Add the version bridge for `BYTE` in the `GUID` module.

[junkmd]

From https://github.com/enthought/comtypes/pull/694#discussion_r1876991821:

To be sure that BYTE is c_ubyte on any python version comtypes support, shouldn't we do this?

if sys.version_info >= (3, 12):

    from ctypes.wintypes import BYTE

else:

    from ctypes import c_ubyte

    BYTE = c_ubyte