[Azure] Support Realtime API

[deyaaeldeen]

Support Azure Realtime API

In order to do so, this PR refactors the OpenAIRealtimeWebSocket and OpenAIRealtimeWS classes to improve the handling of asynchronous operations required during WebSocket connection setup.

Key Changes

1. New open Method

• Previously, the WebSocket connection was established in the class constructor, which could not handle async operations like fetching Azure AD tokens.
• The new open method enables asynchronous fetching of the Azure AD token and establishes the WebSocket connection afterward.

2. New getAzureADToken Method in AzureOpenAI

• Adds a getAzureADToken method in the AzureOpenAI class to provide refreshed Azure AD tokens.
• The OpenAIRealtimeWebSocket class now uses the AzureOpenAI instance to retrieve the necessary Azure AD token for establishing the WebSocket connection.

[deyaaeldeen]

Closing in favor of #1283