I've never heard of tires alone being the cause for a warranty denial.
Think about it this way, though. Larger tires put much less load/stress on the driveline than a 7,000LB trailer. Towing a trailer doesn't void the warranty, larger tires shouldn't impact it either (unless the tires literally damaged the truck because they were making contact).
2017 GMC Canyon Denali CCLB 4x4, 2.8L Duramax, Red Quartz Tintcoat, BMS Catch Can, GMC floor liners, Weathertech no-drill mud flaps, ARE Z-Series shell
2016 Jeep Grand Cherokee Summit, 3.0 EcoDiesel