[DOC] update default model_access_mode for model group

[rawwar]

Description

I see that when I create model group without mentioning model_access_mode, it is defaulting to private and not restricted.

Model Group creation:

Model group information:

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 1,
      "relation": "eq"
    },
    "max_score": 1.540445,
    "hits": [
      {
        "_index": ".plugins-ml-model-group",
        "_id": "ARQBmosBbA7S7gCnC1jL",
        "_version": 1,
        "_seq_no": 16,
        "_primary_term": 1,
        "_score": 1.540445,
        "_source": {
          "owner": {
            "backend_roles": [
              "admin"
            ],
            "custom_attribute_names": [],
            "roles": [
              "own_index",
              "all_access"
            ],
            "name": "admin",
            "user_requested_tenant": null
          },
          "created_time": 1699095841739,
          "access": "private",
          "latest_version": 0,
          "last_updated_time": 1699095841739,
          "name": "test111",
          "description": "This is a test model group"
        }
      }
    ]
  }
}

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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[dhrubo-os]

@rbhavna Could you please review this PR? Thanks.

[rbhavna]

yes it is expected. The default it private: https://opensearch.org/docs/latest/ml-commons-plugin/model-access-control/#registering-a-private-model-group

[rawwar]

yes it is expected. The default it private: https://opensearch.org/docs/latest/ml-commons-plugin/model-access-control/#registering-a-private-model-group

Thanks for confirming. So, we can merge the PR? @dhrubo-os , @rbhavna