Save artifacts from RemoteA2aAgent to Orchestrator session

** Please make sure you read the contribution guide and file the issues in the right place. **
[Contribution guide.](https://google.github.io/adk-docs/contributing-guide/)

**Is your feature request related to a problem? Please describe.**

> Already asked a question under [discussion](https://github.com/google/adk-python/discussions/3112) , but BOT answer me with nonsense respond

> Please introduce information how to pass artifacts ( like files ) from RemoteA2aAgent to the Orchestrator Agent session.

**Describe the solution you'd like**
A clear and concise description of what you want to happen.

> By adding relevant documentation

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

> Introduce Discord channel or any other live community channel where people can get relevant information about issues from community

**Additional context**
Add any other context or screenshots about the feature request here.

> Main documentation is not updated with new code implementation and lack information. BOT can response but his response are rarely correct