[BUG] Simulate ingest pipeline API throws illegal_argument_exception if remove processor is used

[gaobinlong]

Describe the bug

When calling simulate ingest pipeline API, if the remove processor is used and the metadata field _version_type is not specified for the document, then the API always throws illegal_argument_exception which is not as expected.

This bug relates to this line which was added in this PR: #10895 :

OpenSearch/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java

Line 91 in 074bc6a

String versionType = document.getFieldValue(IngestDocument.Metadata.VERSION_TYPE.getFieldName(), String.class);

I'll open a PR to fix this bug and add some yml test for it.

To Reproduce
Steps to reproduce the behavior:

POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "processors": [
      {
        "remove": {
          "field": "foo"
        }
      }
    ]
  },
  "docs": [
    {
      "_source": {
        "foo": "bar"
      }
    }
  ]
}

Expected behavior
Simulate ingest pipeline API runs well no matter the metadata field _version_type is specified or not.

Host/Environment (please complete the following information):

• OS: [macOS]
• Version [main]