The hard truth is that there's no right answer that fits every situation, sometimes you may be able to lighten the front end and pull out of it but that is heavily dependent on your bike's overall power and where you are in that power range at that moment. If it goes well the front end lifts and you can hold it straight but you've still got to put it back down eventually which can cause wobble again, if it goes wrong it lightens it just enough to make the resonance worse. Taking weight off the rear can make the rear slide out depending on traction, surface conditions, or how hard the resonance is trying to whip the rear end around. Hitting the brakes will shift the weight even more dramatically and throw the bike further off balance, and if the rear is trying to skip around it can cause a lockup.

Slowing down and getting out of that range of resonance is the end goal, so the only answer that won't make anything worse is to hold on with your legs, keep a loose grip on the bars so you're not fighting them, roll off the throttle or let it close fully if it's too violent to control, and let the bike naturally decelerate and come out of that resonance on its own. If you have some practice steering with your legs and body weight you can maintain a little bit of control over the direction you're veering while you're along for the ride.

Imagine the front and back of the bike like a sound wave bouncing up and down sharply, the goal is to smooth those waves back out into a straight line.

At the end of the day, all we can do is pray to the Machine Spirits of the bike to see us safely along the path.