[Azure OpenAI] Add file management support for Azure OpenAI Provider

[jesse-bos-dij]

I was really excited to see Azure OpenAI provider support added to the SDK! However, I noticed that file management is not yet supported. Attempting any file operation throws:
Provider [Laravel\Ai\Providers\AzureOpenAiProvider] does not support file management.

Azure OpenAI does support the Files API and File Search / Vector Stores, so it would be great to have parity with OpenAiProvider here. This is especially relevant for enterprise users who are required to use Azure OpenAI (compliance, data residency) and need FileSearch for RAG-based agents.