fix: add phone_number_sid to import

[salah93]

https://github.com/twilio/terraform-provider-twilio/blob/main/twilio/resources/messaging/v1/README.md#twilio_messaging_services_phone_numbers_v1

[qrnik]

@childish-sambino any chance to get it merged? importing twilio_messaging_services_phone_numbers_v1 resource results in its replacement:

  # twilio_messaging_services_phone_numbers_v1.number must be replaced
  # (imported from "MGXXXX/PNXXX")
  # Warning: this will destroy the imported resource
-/+ resource "twilio_messaging_services_phone_numbers_v1" "number" {
      ~ id               = "MGXXX/PNXXX" -> (known after apply)
      + phone_number_sid = "PNXXX" # forces replacement
        service_sid      = "MGXXX"
      ~ sid              = "PNXXX" -> (known after apply)
    }