[BUG] `POST /_plugins/_replication/music-names/_pause` API requires an empty request body

[dblock]

What is the bug?

[INFO] => POST /_plugins/_replication/music-names/_pause ({}) [application/json] 
[INFO] <= 400 (application/json) | {
  "error": {
    "root_cause": [
      {
        "type": "parse_exception",
        "reason": "request body or source parameter is required"
      }
    ],
    "type": "parse_exception",
    "reason": "request body or source parameter is required"
  },
  "status": 400
}

An empty request body shouldn't be needed.

What is the expected behavior?

An empty body should not be required. Documentation (https://opensearch.org/docs/latest/tuning-your-cluster/replication-plugin/api/) is also unclear even though it says {} in the example, but unsure how one can guess that without trying.

[soosinha]

[Triage - attendees 1 2 3 4]

@dblock What is the convention in OpenSearch core APIs ?

[skumarp7]

Hi @soosinha, @ankitkala, @monusingh-1

Can you assign this to me ? I would like to contribute to this issue.