COVID-19 Diagnostics Market Size & Forecasts 2026-2035, By Segments (Mode, Product & Service, Test Type, End-use, Sample Type), Growth Opportunities, Innovation Landscape, Regulatory Shifts, Strategic Regional Insights (U.S., Japan, China, South Korea, UK, Germany, France), and Competitive Dynamics (Roche, Abbott, Siemens Healthineers, Thermo Fisher Scientific, Bio-Rad Laboratories)