Alternative for 'ResponseStreamEventType' from 'azure.ai.projects.models' is not documented

- **Package Name**: azure-ai-projects
- **Package Version**: 2.0.0b4 and above
- **Operating System**: Windows
- **Python Version**: 3.13.9

**Describe the bug**
The `ResponseStreamEventType` enum is no longer available in `azure.ai.projects.models` using package version 2.0.0b4 or above. This is used to help capture streaming response events from `openai_client.responses.create()` without the need for string literals. This change was not documented in CHANGELOG.md or in Foundry code samples despite the GitHub repo samples being updated.

**To Reproduce**
Steps to reproduce the behavior:
1. Use the sample code from Foundry for workflows OR Attempt to import `ResponseStreamEventType` from `azure.ai.projects.models`
2. Run-time error `Cannot import name 'ResponseStreamEventType' from 'azure.ai.projects.models'`

**Expected behavior**
The package import to exist or for clear breaking change documentation to migrate to string literals in the CHANGELOG.md

**Screenshots**
Official Foundry code samples and documentation say beta4 and above is supported.