Add Gemini 3.1 Pro Preview to copilot models

[riasvdv]

[rekram1-node]

Fixing name, also from copilot api it doesnt list audio or video support.

"vision": {
"max_prompt_image_size": 3145728,
"max_prompt_images": 10,
"supported_media_types": [
"image/jpeg",
"image/png",
"image/webp"
]
}