OTC Pet Medication Market Size & Forecasts 2026-2035, By Segments (Distribution Channel, Dosage Form, Pet Type, Medication Type), Growth Opportunities, Innovation Landscape, Regulatory Shifts, Strategic Regional Insights (U.S., Japan, China, South Korea, UK, Germany, France), and Competitive Dynamics (Zoetis, Elanco, Merck Animal Health, Boehringer Ingelheim, Bayer Animal Health)