URL-encoding not handled for proxy username.(http-client)

[yangy-23]

Describe the bug
Our Zscaler proxy requires @ to be used within the username. Because the username and password are specified as part of a URL, they must be URL-encoded by the caller; otherwise consider what would happen if the user's password or username contained an @ or a :, etc.

To Reproduce
Steps to reproduce the behavior:

1. Self-hosted runner with http_proxy and https_proxy setup with user@name:password@proxy_url:proxy_port
2. For URL encoding. The @ within http_proxy and https_proxy will be replaced with %40 for URL encoding
3. http-client load the username as plain text without decoding

Expected behavior
Expect http-client decode username and password when needed.

Screenshots