[BUG] Creating no auth data connection fails validaiton

[derek-ho]

Describe the bug

Try to create a data connection to a cluster running without security:

You get the following error:

Request payload:
{"dataSourceAttr":{"endpoint":"http://localhost:9201","auth":{"type":"no_auth","credentials":{"username":"","password":"","service":"es"}}}}

Response:
{statusCode: 400, error: "Bad Request",…}
error
: 
"Bad Request"
message
: 
"[request body.dataSourceAttr.auth.credentials]: types that failed validation:\n- [request body.dataSourceAttr.auth.credentials.0.service]: definition for this key is missing\n- [request body.dataSourceAttr.auth.credentials.1.region]: expected value of type [string] but got [undefined]"
statusCode
: 
400

Even though the cluster is reachable:

➜  opensearch-3.0.0-SNAPSHOT curl http://localhost:9201
{
  "name" : "b0f1d89879ca",
  "cluster_name" : "opensearch",
  "cluster_uuid" : "jz2tgeuDTk6XgiDEerKtMw",
  "version" : {
    "distribution" : "opensearch",
    "number" : "3.0.0-SNAPSHOT",
    "build_type" : "tar",
    "build_hash" : "3125b948029609f354d3153f8ca6391638daefc7",
    "build_date" : "2024-02-29T01:10:41.128733293Z",
    "build_snapshot" : true,
    "lucene_version" : "9.11.0",
    "minimum_wire_compatibility_version" : "2.13.0",
    "minimum_index_compatibility_version" : "2.0.0"
  },
  "tagline" : "The OpenSearch Project: https://opensearch.org/"
}

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Expected behavior
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[BionIT]

I can reproduce this bug
before creating the data source, click test connection with no auth >> show error
after data source is created, then click test connection >> no error

[BionIT]

The error is due to payload validation for test connection, happy to work on it! We need to add tests for this validate endpoint