Functional Coffee Market Size, Share & Industry Analysis, By Product Type (Whole Bean, Ground Coffee, Ready-to-Drink (RTD), and Instant Coffee), By Function (Weight Management, Mood Enhancement, Digestive Health, and Immunity Boost), By Distribution Channel (Foodservice and Retail (Supermarkets & Hypermarkets, Specialty Stores, Online Retail and Others), and Regional Forecast, 2026-2034