fix: PD002 checks for zero unconditional RouteRules

[DinoChiesa]

Alter plugin PD002 to now check for zero unconditional RouteRules.

Without this change PD002 checks for more than one unconditional RouteRule. But it does not check for exactly one. With zero unconditional RouteRules, at runtime the proxy can generate this error:

{
  "fault": {
    "faultstring": "Unable to route the message to a Target Endpoint",
    "detail": {
      "errorcode": "messaging.runtime.RouteFailed"
    }
  }
}

This change ALSO modifies PD002 to flag the redundant RouteRules when there are multiple. Previously it flagged every unconditional RouteRule (1..n); now it flags only 2..n.