Fix enode URL parse failure due to enode prefix

[sergerad]

Relates to PR #8188

Hack to fix parsing of enode strings with the URL crate.

The enode prefix causes the parser to go down this host parsing logic which does not handle ipv4:

    pub fn parse_opaque(input: &str) -> Result<Self, ParseError> {
// ...snip...
        if input.find(is_invalid_host_char).is_some() {
            Err(ParseError::InvalidDomainCharacter)
        } else {
            Ok(Host::Domain(
                utf8_percent_encode(input, CONTROLS).to_string(),
            ))
        }
    }

[Rjected]

ah I see, this should work