Stem Cell Assay Market Size & Forecasts 2026-2035, By Segments (Kit, Detection Kit, End-users, Application, Instrument), Growth Opportunities, Innovation Landscape, Regulatory Shifts, Strategic Regional Insights (U.S., Japan, China, South Korea, UK, Germany, France), and Competitive Dynamics (Thermo Fisher Scientific, Lonza Group, Merck KGaA, Charles River Laboratories, STEMCELL Technologies)