The way I understand it, adaptive optics, small sub-mirrors controlled by servos, are used to introduce distortions in a mirror that compensate for the effects of atmospheric seeing, so having adaptive optics in an orbital telescope above the atmosphere makes no sense at all.

However, it appears that in this case, the mirror is of such large aperture it cannot be sent into orbit in one piece, so it is deployed as an adaptive optics system simply to make it more compact, and allow it to be folded into a smaller volume for launch, and unfolded when in orbit. This makes sense, but if I'm missing something, please let me know.