chore: update model name from gpt-4.1-mini to gpt4.1-mini#754

Roopan-Microsoft merged 3 commits intobyoc-researchermicrosoft/Build-your-own-copilot-Solution-Accelerator:byoc-researcherfrom

chore/rename-gpt-4.1-mini-to-gpt4.1-minimicrosoft/Build-your-own-copilot-Solution-Accelerator:chore/rename-gpt-4.1-mini-to-gpt4.1-miniCopy head branch name to clipboard