clippy: Map to an error type instead of using allowing result_unit_err in components/url

[ektuu]

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes are related to clippy: fix warnings in /Components/url #31832
• These changes do not require tests because they do not change functionality.

[Loirooriol]

Some points:

• When you receive feedback in a PR, just update the old one, don't create a new one
• The only difference from cd28798 is that you avoided inserting a space before #![deny(unsafe_code)], but you are still adding unnecessary newlines
• Is there any reason to reorder the methods?
• The template for pull requests has a list of things that you need to test, and check if they hold.
• In particular, ./mach test-tidy is complaining: https://github.com/servo/servo/actions/runs/8395608656/job/22995237911?pr=31834
• What are the warnings that you are trying to address?

[ektuu]

Thankyou for your feedback. I will address the issues mentioned.

In the above PR, I used a custom error type to address the warnings of functions returning 'Result<_, ()>'.
Methods such as set_username, set_ip_host, set_password, to_file_path, and from_file_path have been modified to return a Result type with UrlError instead of (). Previously existing method definitions have been modified or removed to align with the new error handling strategy.

[ektuu]

@Loirooriol
I've addressed the issues. can you please review?

[Loirooriol]

What's the reason for reordering the methods?

[ektuu]

Methods have been reordered to align with the new error handling strategy. The methods which use custom error UrlError have been put together to enhance readability of the code. Would you want me to reorder them ?

[servo-wpt-sync]

🛠 These changes could not be applied onto the latest upstream WPT. Servo's copy of the Web Platform Tests may be out of sync.

[mrobinson]

Looks like I was wrong here. This didn't go to the merge queue, because it is still waiting on a review from @Loirooriol, as he requested changes earlier.

[Loirooriol]

I share eerii's doubts about whether this is actually an improvement, but I'm fine with the change.

[mrobinson]

I also agree that as it is, this isn't super useful, but it does prepare the code for better error handling in the future.

[mrobinson]

Looks like the failure was an infrastructure issue for the Android build:

Error: Exception in thread "main" java.net.ConnectException: Connection timed out