Add support to Google ADK for agentic LLM workflows

### Description

In the https://github.com/apache/airflow/pull/62825 the AgentOperator and agent decorator was introduce to official repo with PydanticAI support.

Now we want to use an alternative framework like ADK to improve capabilities of AgentOperator with all main features from ADK.

### Use case/motivation

We do like to use agentic workflow with another framework rather than PydanticAI, in this case ADK.

The framework could offer some features more robust than PydanticAI.

### Related issues

https://github.com/apache/airflow/pull/62825

### Are you willing to submit a PR?

- [x] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)