AzureOpenAIServerModel doesn't support Microsoft Entra ID authentication

[edwardmfho]

The current AzureOpenAIServerModel can only be authenticated via API key. While this is useful, does not account for the use of Microsoft Entra ID to authenticate.

We can make a simple change to the AzureOpenAIServerModel to enable such authentication method. Pull request to be created to address this issue.

The usage example can be found below:

import os
from smolagents.models import AzureOpenAIServerModel
from azure.identity import DefaultAzureCredential, get_bearer_token_provider

    token_provider = get_bearer_token_provider(
        DefaultAzureCredential(),
         "https://cognitiveservices.azure.com/.default")

   
    model = AzureOpenAIServerModel(
        args.model_id,
        azure_endpoint=os.getenv("AZURE_OPENAI_ENDPOINT"),
        azure_deployment=os.getenv("AZURE_DEPLOPYMENT_NAME"),
        azure_ad_token_provider=token_provider,
        api_version=os.getenv("AZURE_API_VERSION"),
        custom_role_conversions=custom_role_conversions,
        max_completion_tokens=8192,
        reasoning_effort="high",
    )   

[edwardmfho]

Code implemented in #592