Describe the bug
If I put agent-card.json (as specified in the a2a docs) to the directory with agent, it's not found. Instead, it looks for the deprecated agent.json. It was deprecated here.

To Reproduce
Steps to reproduce the behavior:

1. Make agent.
2. Add agent-card.json
3. Try to use a2a and fail miserably.

Expected behavior
It would support the current standard.

Desktop (please complete the following information):

OS: Windows 11
Python version(python -V): Python 3.12.8
ADK version(pip show google-adk): 1.11.0

Model Information:
Any model.