Bundled CLIProxyAPI's installation and update does not respect `http_proxy`

[spencerwooo]

CLIProxyAPI installation or updates does not go through http_proxy set via environment variables.

This occurs 1) first time running ccs config (which triggers the download of CLIProxyAPI, and 2) updating CLIProxyAPI via ccs cliproxy --update.

Expected behaviour: respect http_proxy, https_proxy, and all_proxy environment variables when doing network requests.