Bug in pure mcp example (missing tool name)

### What happened?

https://github.com/a2aproject/a2a-samples/blob/f140c6d5bc90297f448fdf73ab4b32c16f7cf60c/samples/python/agents/a2a-mcp-without-framework/src/no_llm_framework/server/agent.py#L153

but in jinja

https://github.com/a2aproject/a2a-samples/blob/f140c6d5bc90297f448fdf73ab4b32c16f7cf60c/samples/python/agents/a2a-mcp-without-framework/src/no_llm_framework/server/called_tools_history.jinja#L2

In jinja, should use "tool.tool" instead to avoid missing tool name in history? (or agent.py should use "name" as key?)

### Relevant log output

```shell
After writting the rendered template, currently the prompt looks like the following

...
Previous tools have been called.
- Tool:
- Arguments: {...
```

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