[Bug]: Failed to fetch: rsa-4.9.1-py3-none-any.whl`

### What happened?

When I try to run crewai or google-adk agent:

1. `cd agent/A2A/samples/python/agents/crewai`
2. `uv run .`

I see failed to download error. Also tried below:

`PIP_CONFIG_FILE=~/myproject/.pip/pip.conf uv run .`

~/myproject/.pip/pip.conf -

```
[global]
trusted-host = files.pythonhosted.org pypi.org pypi.python.org
```

### Relevant log output

```shell
× Failed to download `rsa==4.9.1`
├─▶ Failed to fetch: `https://files.pythonhosted.org/packages/64/8d/0133e4eb4beed9e425d9a98ed6e081a55d195481b7632472be1af08d2f6b/rsa-4.9.1-py3-none-any.whl`
╰─▶ HTTP status client error (403 Forbidden) for url (https://files.pythonhosted.org/packages/64/8d/0133e4eb4beed9e425d9a98ed6e081a55d195481b7632472be1af08d2f6b/rsa-4.9.1-py3-none-any.whl)
help: `rsa` (v4.9.1) was included because `a2a-samples-image-gen` (v0.1.0) depends on `google-genai` (v1.13.0) which depends on `google-auth` (v2.39.0) which depends on `rsa`
```

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

The error occurs when running the crewai sample in `agent/A2A/samples/python/agents/crewai`. The issue is a 403 Forbidden error fetching the `rsa` package from PyPI. First, check the `pyproject.toml` or `requirements.txt` in that directory to see the dependencies. Investigate if the issue is network-related, a PyPI mirror problem, or a dependency conflict. Test with different Python package managers (uv, pip) and network configurations to reproduce and isolate the cause.

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