chore(generative_ai): update model references to stable gemini models (#14117)#14460

aditya-cyberverse wants to merge 2 commits into

GoogleCloudPlatform:mainGoogleCloudPlatform/python-docs-samples:mainfrom

aditya-cyberverse:fix/generative-ai-model-namesaditya-cyberverse/python-docs-samples:fix/generative-ai-model-namesCopy head branch name to clipboard