Global Cloud Telephony Service Market Size, Share, and Strategic Analysis By Deployment (Hosted, Cloud), By Enterprise Size (Small & Medium Enterprises, Large Enterprises), By Network (PSTN, VoIP), By Application (Conferencing, Multi-Level IVR, Sales & Marketing, CRM), By Industry Vertical (BFSI, Healthcare, Retail, Telecom & IT, Government, Education) Industry Outlook, Competitive Landscape, Technology Trends & Forecast 2025–2034