refactor(dpi/http): drop dead inner parts.len() >= 3 check

[obchain]

Summary

analyze_http (src/network/dpi/http.rs) gates first-line parsing on parts.len() >= 3 and then re-checks the same condition inside the request branch:

if parts.len() >= 3 {
    if first_line.starts_with("HTTP/") {
        info.version = parse_http_version(parts[0]);
        info.status_code = parts[1].parse::<u16>().ok();
    } else if is_http_method(parts[0]) {
        info.method = Some(parts[0].to_string());
        info.path = Some(parts[1].to_string());
        if parts.len() >= 3 {
            info.version = parse_http_version(parts[2]);
        }
    } else {
        return None;
    }
} else {
    return None;
}

parts is not mutated between the outer guard (line 30) and the inner check (line 39), so the inner if is always true and parse_http_version(parts[2]) runs unconditionally. Drop the inner conditional and call the function directly; the expanded comment records the invariant the outer guard provides so a future reader doesn't reintroduce the check.

Behavior is unchanged.

Closes #302.

Verification

• cargo test --lib: all pass (4 in network::dpi::http / https).
• cargo clippy --all-targets -- -D warnings: clean.
• cargo fmt --check: clean.

Notes

Fits the recent refactor(dpi/...) cleanup series — same shape as #296 (ssh dead conditional) and #279 (snmp unreachable arm). Net diff is 3 added / 4 removed in a single block; no test churn since both code paths through the request branch are already exercised by test_http_request.

[domcyrus]

@obchain Thanks a lot for your PR, LGTM!