plugin-flow-builder: add whatsapp CTA url button

[Iru89]

Description

Now we can have a whatsapp node containing a single button that redirects to a URL. When the plugin receives the JSON that defines a node of this type it will use a WhatsappCTAUrlButton from @botonic/react to render it.

Context

Example of JSON defining this node

{
  "id": "a0898927-42f6-45a5-8c6a-66bdd92f0e13",
  "code": "test url",
  "is_code_ai_generated": false,
  "meta": {
    "x": -80.59924537568803,
    "y": -221.97477364675905
  },
  "follow_up": null,
  "target": null,
  "flow_id": "8d527e7d-ea6d-5422-b810-5b4c8be7657b",
  "type": "whatsapp-cta-url-button",
  "content": {
    "text": [
      {
        "message": "this is a text",
        "locale": "es"
      },
      {
        "message": "this is a text",
        "locale": "it"
      }
    ],
    "header": [
      {
        "message": "this is a header",
        "locale": "es"
      }
    ],
    "footer": [
      {
        "message": "this is a footer",
        "locale": "es"
      }
    ],
    "button": {
      "id": "85fd9960-1892-4117-96af-e07f5c0c76ca",
      "text": [
        {
          "message": "this is the text of a btn url",
          "locale": "es"
        }
      ],
      "url": [
        {
          "id": "945a346d-ab2f-4dc0-8206-5be281ee9799",
          "locale": "es"
        }
      ],
      "target": null,
      "payloads": [],
      "hidden": [],
    }
  }
}

To document / Usage example

[linear]

BLT-700 TASK - Add whatsapp CTA URL Button on flow builder plugin