System message `reaction_revoked` should contain, which reaction was revoked

[Antreesy]

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Steps to reproduce

1. Post a message
2. Add a reaction
3. Remove a reaction

Actual behaviour

POST to api/v1/reaction/{token}/{id}:

"data": {
    "\ud83d\udc4d": [
        {
            "actorType": "users",
            "actorId": "antreesy",
            "actorDisplayName": "Max Southgate",
            "timestamp": 1746019885
        }
    ]
}

DELETE to api/v1/reaction/{token}/{id}?reaction=%F0%9F%91%8D:

"data":{}

This also triggers GET request to api/v1/reaction/{token}/{id}, as other clients don't know, which and by whom a reaction was removed

GET messages after long polling, or chat loading:

[
  {
      "id": 576,
      "message": "{file}",
      "reactions": {
          "\ud83d\ude00": 1
      },
  },
  {
      "id": 577,
      "message": "Reaction deleted by author",
      "systemMessage": "reaction_deleted",
      "parent": {
          "id": 576,
      }
  },
  {
      "id": 578,
      "message": "You deleted a reaction",
      "systemMessage": "reaction_revoked",
      "parent": {
          "id": 576,
      }
  }
  {
      "id": 579,
      "message": "\ud83d\ude00", // This is missing on reaction_revoked
      "systemMessage": "reaction",
      "parent": {
          "id": 576,
          "reactions": {
              "\ud83d\ude00": 1
          },
      }
  }
]

Talk app

Talk app version: dev