Read a saved image generation request

{  "$schema": "https://example.com/api/v1/schemas/ImageGenerationRun.json",  "billing_state": "string",  "cost_microusd": 0,  "created_at": "2019-08-24T14:15:22Z",  "error_message": "string",  "id": "string",  "model": "string",  "operation": "string",  "page_id": "string",  "project_id": "string",  "prompt": "string",  "result_media_id": "string",  "source_media_id": "string",  "state": "string",  "target_fingerprint": "string",  "target_layer_id": "string",  "workspace_id": "string"}