fix: support auto URLs in _sanitize_web3_url() helper func

[mikeshultz]

What I did

Fixes an issue caused by the host: auto setting in ape-hardhat's config.

Traceback (most recent call last):
  File "/home/mike/dev/ape/src/ape/logging.py", line 102, in emit
    msg = handler(msg)
          ^^^^^^^^^^^^
  File "/home/mike/dev/ape/src/ape_ethereum/provider.py", line 92, in _sanitize_web3_url
    sanitized_url = sanitize_url(rest[0])
                    ^^^^^^^^^^^^^^^^^^^^^
  File "/home/mike/dev/ape/src/ape/logging.py", line 278, in sanitize_url
    url_obj = URL(url).with_user(None).with_password(None)
              ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mike/.venvs/ape-dev/lib/python3.11/site-packages/yarl/_url.py", line 838, in with_user
    raise ValueError("user replacement is not allowed for relative URLs")
ValueError: user replacement is not allowed for relative URLs

How I did it

Does not try and sanitize auto URLs

Checklist

• All changes are completed
• New test cases have been added
• Documentation has been updated