[BUG] Throw class_cast_exception when adding _version field to docs in ingest simulate API

[gaobinlong]

Describe the bug
When adding _version field to each doc in the request body of ingest simulate API, the API returns class_cast_exception with 500 status code no matter the field is a string or an integer.

To Reproduce
Request:

POST _ingest/pipeline/_simulate
{
  "pipeline" : {
    "description": "test",
    "processors": [
        {
          "set": {
            "field": "foo",
            "value": "zoo"
          }
        }
    ]
  },
  "docs" : [
    {
            "_version" : "123",
            "_source" : {
                "foo" : "bar"
            }
        }
  ]
}

Response:

{
  "error": {
    "root_cause": [
      {
        "type": "class_cast_exception",
        "reason": "class java.lang.String cannot be cast to class java.lang.Long (java.lang.String and java.lang.Long are in module java.base of loader 'bootstrap')"
      }
    ],
    "type": "class_cast_exception",
    "reason": "class java.lang.String cannot be cast to class java.lang.Long (java.lang.String and java.lang.Long are in module java.base of loader 'bootstrap')"
  },
  "status": 500
}

Expected behavior
Ingest simulate API can accept _version field and handle it correctly.

Host/Environment (please complete the following information):

• OS: [MacOS]
• Version [OpenSearch 2.9]

Additional context
Add any other context about the problem here.

[gaobinlong]

Closed by #10478.