Fixes#596
Update `azure_openai_complete` function to accept a model parameter with a default value of 'gpt-4o-mini'.
* Modify the function signature of `azure_openai_complete` to include a `model` parameter with a default value of 'gpt-4o-mini'.
* Pass the `model` parameter to the `azure_openai_complete_if_cache` function instead of the hardcoded model name 'conversation-4o-mini'.
---
For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/HKUDS/LightRAG/issues/596?shareId=XXXX-XXXX-XXXX-XXXX).
df69d386c5