Old construction, replacing light switch, bundled ground
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.