Fix incorrect IPv6 validation logic in String::is_valid_ip_address()

[PrIzRaKDev]

Rewrites the IP validation logic to correctly handle IPv6 and IPv4. Prevents false positives such as 2001:db8:::1 and improves overall compliance with standard IP formatting rules.

Before:

before.mp4

After:

after.mp4

Closes #112511

[Ivorforce]

Hello, thank you for opening a pull request!

I'm noticing your code doesn't respect our code guidelines, please have a look and review your pull request: https://contributing.godotengine.org/en/latest/engine/guidelines/index.html

It may be especially worthwhile for you to set up a pre-commit hook.

While I haven't reviewed the code yet in detail, I have a gut feeling that it can be simplified. The old code (albeit not always correct, going by the linked issue) seemed to have done a decent job with a lot less logic. I'm guessing it will be possible to keep a similar amount of complexity for the fix.

[PrIzRaKDev]

Hello, thank you for opening a pull request!

I'm noticing your code doesn't respect our code guidelines, please have a look and review your pull request: https://contributing.godotengine.org/en/latest/engine/guidelines/index.html

While I haven't reviewed the code yet, I have a gut feeling that the code can be simplified. The old code (albeit not always correct) seemed to have done a decent job with a lot less logic. I'm guessing it will be possible to keep a similar amount of complexity for the fix.

Hello. Okay, I will take your comments into account and correct the code.