DocumentIntelligenceConverter should not set a default api_version

[evozondatascience]

I wanted to use markitdown[az-doc-intel] and I encountered a problem on api_version.

1. Apparently the Azure document intelligence has a default version of '2024-11-30' set inside the DocumentIntelligenceClient from azure.
2. Inside the DocumentIntelligenceConverter class the api version is set on default as being api_version: str = "2024-07-31-preview".
3. For most of azure document intelligence deployments they don't even specify an api_version endpoint anymore and the default is always 2024-11-30. So if you pass an empty one the DocumentIntelligenceConverter will set the default to the wrong one which will cause azure to give 404 resource not found.

The fix: would be that DocumentIntelligenceConverter accepts api_version as null and it can safely let the DocumentIntelligenceClient take care of setting the right api_version.