Get a prompt revision by the prompt’s slug and version

$revision = $pj->getPrompt('greeting', 'production');

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "promptId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "modelParams": {
    "maxCompletionTokens": null,
    "temperature": null,
    "topP": null,
    "verbosity": null,
    "reasoningEffort": null,
    "reasoningSummary": null,
    "serviceTier": "default"
  },
  "responseFormat": {
    "type": "text"
  },
  "messages": [
    {
      "content": "<string>"
    }
  ],
  "tools": [
    {
      "type": "web_search",
      "allowedDomains": [
        "<string>"
      ]
    }
  ],
  "systemInstruction": "<string>"
}