Upgraded all GPT-3.5 demo apps to new GPT-4o-mini.

• Switched from GPT-3.5-turbo-1106 to the newly released GPT-4o-mini for all relevant demo apps.

• Ensured immediate adoption of OpenAI's latest model for enhanced performance and accuracy.

• Updated app descriptions to reflect the transition to GPT-4o-mini. 🚀