GitLab

Refactor URL validation function

- The check for private IP addresses often did not yield the expected results, especially with errors like: `[Errno -2] Name or service not known`.
- Removed the check for private IP addresses in the URL validation process.
- Simplified the `validate_url` function to focus on validating the URL format and checking the existence of the URL using a HEAD request.

Updated Croatian translation for user interface text