Fix "CORS Rejected - Invalid origin" issue when origin header is empty

[ahamlat]

PR description

Fix "CORS Rejected - Invalid origin" issue when the origin allowed hosts is set to * and actual origin is empty (not null, but empty).

The regex may appear a bit weird at first glance, but this change is more related to the change in Vertx implementation between 4.3.5 and 4.5.4. This new regex will make sure that Vertx CorsHandler will try to match origin values to that regex.

Vertx 4.3.5 (old regex in Besu is .*)

public CorsHandlerImpl(String allowedOriginPattern) {
    Objects.requireNonNull(allowedOriginPattern);
    if ("*".equals(allowedOriginPattern)) {
      allowedOrigin = null;
    } else {
      allowedOrigin = Pattern.compile(allowedOriginPattern);
    }
    allowedOrigins = null;
  }

Vertx 4.5.4 (regex in Besu is .*://.*)

  public CorsHandler addRelativeOrigin(String origin) {
    Objects.requireNonNull(origin, "'origin' cannot be null");

    if (relativeOrigins == null) {
      if (origin.equals(".*")) {
        // we signal any as null
        return this;
      }
      relativeOrigins = new LinkedHashSet<>();
    } else {
      if (origin.equals(".*")) {
        // we signal any as null
        throw new IllegalStateException("Cannot mix '/.*/' with relative origins");
      }
    }
    relativeOrigins.add(Pattern.compile(origin));
    return this;
  }

Fixed Issue(s)

#6983

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