### ✅ Uploading PYQ Fails – Missing `uploader` & `branch` not ObjectId**

🛠️ Uploading PYQ Fails – Missing uploader & branch not ObjectId

🐛 Description:

Uploading a PYQ fails due to two schema validation issues:

1. branch expects an ObjectId, but receives a string.
2. uploader field is missing in the payload.

---

💥 Error Response:

{
  "error": "Validation failed",
  "details": {
    "branch": {
      "stringValue": "\"CSE\"",
      "valueType": "string",
      "kind": "ObjectId",
      "value": "CSE",
      "path": "branch",
      "name": "CastError",
      "message": "Cast to ObjectId failed for value \"CSE\" at path \"branch\""
    },
    "uploader": {
      "name": "ValidatorError",
      "message": "Path `uploader` is required.",
      "properties": {
        "message": "Path `uploader` is required.",
        "type": "required",
        "path": "uploader"
      },
      "kind": "required",
      "path": "uploader"
    }
  }
}
✅ Expected Behavior:
PYQ should be uploaded successfully when valid data is provided.

❌ Actual Behavior:
Validation fails and returns 400 status.