Fixed URL-encoded characters in basic auth credentials (#1623)

[abhishekjoshi13]

When providing credentials in the URL that contain URL-encoded characters (like %40 for @), the urlsplit output was not being decoded before being passed to AuthCredentials. This resulted in the raw encoded string being Base64 encoded, causing server rejection. I injected urllib.parse.unquote in argparser.py to decode url.username and url.password prior to generating the Basic Auth headers

[abhishekjoshi13]

HI team, just a quick heads up. The fix for decoding credentials in the URL is pushed and ready for review. I noticed the CI pipeline is throwing some failures, but after reviewing the server logs, they appear to be unrelated upstream issues:

1. test_cli_ui.py::test_naked_invocation - Failing on python 3.12 due to the argparse formatting changes(quotes being added around choices)
2. test_encoding.py - The big5 charset tests appear to be failing across environments.
   Let me know if you would like me to write a dedicated unit test for this URL decoding fix, or if there is anything else you need from me to get this merged.