You should let the WR terminate on it's own, it won't reseed much in a thick sand of clover, and a little reseeding is harmless in a food plot. It's not hurting the growth of the clover, but rather helping the clover by providing protection, and it doesn't use the same nutrients as clover. The dead stalks will eventually provide carbon to feed your clover, so the longer you let them grow, the more carbon you get back. If you didn't have clover a typical method would be to spray with roundup then do a throw-n-mow or a no-till planting, it's very easy stuff to kill. But mowing it now on a good clover stand may create a mat that could suffocate your clover. When farmers mow a thick stand of rye in the spring they always rake and bale it to get it off the field.
Agree with everything said above. I would add that mowing high also leaves the rigid and almost prickly stems standing for a while. I have nothing but observance as proof but it seems to me that deer are reluctant to stick their nose down through the dead stems to eat the clover down to the ground and going into the heat of summer your clover is a little taller than what it would be without the dead WR.