[Misc] Enable proxy support in benchmark script

[jsato8094]

This PR allows the benchmark script to respect HTTP proxy settings specified through environment variables. This is particularly useful when running the script in environments where network access requires proxy configurations. The trust_env=True parameter instructs aiohttp to use proxy settings from environment variables such as HTTP_PROXY and HTTPS_PROXY.

For more details on proxy support in aiohttp, refer to the official documentation: Proxy Support in aiohttp.

[github-actions]

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