fix: add Hugging Face API key to StableDiffusionV3 parameters and remove deprecated model option

[Irozuku]

This pull request updates the Stable Diffusion v3 model integration in DashAI to support loading private models from Hugging Face by allowing users to provide an API key. It also improves error handling during authentication and model loading. Additionally, it removes an unused model option from the schema.

Authentication and API key support:

• Added a new huggingface_key field to the StableDiffusionSchema to allow users to specify their Hugging Face API key for accessing private models.
• Updated the model initialization to authenticate with Hugging Face using the provided API key, with error handling for failed logins.
• Imported the login function from huggingface_hub to enable authentication.

Model selection schema update:

• Removed "stabilityai/stable-diffusion-3-medium-tensorrt" from the list of available model options in the schema, likely because it is deprecated or unsupported.

Robust model loading:

• Improved error handling when loading the selected model, raising a clear error if the model cannot be loaded.