Summary:

For enterprise Azure Open AII LLM's application key is mandatory for authorization.

- Updated `LmChatAzureOpenAi.node.ts` to include the ability to pass the application key through headers for user authorization.
- Addresses the issue where LLM returns a 422 error if the application key is not provided in enterprise Azure Open AI LLM's.

This change is necessary to enable proper authorization when interacting with Azure OpenAI models.

Review / Merge checklist

• PR title and summary are descriptive. (conventions) <!-- **Remember, the title automatically goes into the changelog. Use `(no-changelog)` otherwise.** -->
• Docs updated or follow-up ticket created.
• Tests included. <!-- A bug is not considered fixed, unless a test is added to prevent it from happening again. A feature is not complete without tests. -->
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)