Yes. Modern code requires switches to be grounded. If you are not using self grounding switches and metal boxes (and you are not), you need to run a wire from the switch ground screw to the bundle. Attaching to the end of any one of those wire will do.
Supplement: While the electrical police are unlikely to come pounding on your door, there is a reason for code. The ground serves as a safety if the switch gets damaged. It prevents the (rare) chance of you flicking a damaged switch and getting a shock. It's worth the trouble. In general, when you do an upgrade or a fix, you bring the device or system up to code if it is possible and reasonable. In this case it is both.