Medium Commercial Vehicles Market Size, Share & Industry Analysis, By Powertrain (ICE, BEV, HEV/PHEV, LPG & Others, and Fuel Cell), By Class (Class 3, Class 4, Class 5, and Class 6), By Type (Tractor Units and Rigid Trucks), By Application (Transportation, Construction, Mining, and Agriculture), and Regional Forecast, 2026–2034