[base] Return error if requested driver is not found. In `open_face_from_buffer` it is possible that a driver is requested but FreeType was built without the requested module. Return an error in this case to indicate that the request could not be satisfied, rather than trying all existing driver modules. * src/base/ftobjs.c (open_face_from_buffer): Return `FT_Err_Missing_Module` if a driver is specified but not found.