[BUG] opensearch-sql CLI doesn't print a error return if http code is 500

[Yury-Fridlyand]

Describe the bug
Some queries cause a error on server side and REST returns a message describing it followed by code 500. In this case CLI doesn't print the error.

opensearchsql> SELECT A, B FROM (SELECT `key` as A, DAYOFWEEK(date1) AS B from calcs) tmp WHERE tmp.B IN (1, 7);
KeyError('datarows')

In such cases I have to use CURL to see the message:

curl -XPOST http://localhost:9200/_plugins/_sql -H 'Content-Type: application/json' -d '{"query" : "SELECT A, B FROM (SELECT `key` as A, DAYOFWEEK(date1) AS B from calcs) tmp WHERE B IN (1, 7);"}'
{
  "error": {
    "reason": "There was internal problem at backend",
    "details": "The following method is not supported in Schema: DAYOFWEEK",
    "type": "UnsupportedOperationException"
  },
  "status": 500
}

The CLI interface is much more convenient for use rather than CURL, so it would be useful to keep using it to see the error message.

Additional context
Low priority

[zhongnansu]

 curl -XPOST http://localhost:9200/_plugins/_sql -H 'Content-Type: application/json' -d '{"query" : "SELECT A, B FROM (SELECT `key` as A, DAYSOFWEEK(customer_first_name) AS B from opensearch_dashboards_sample_data_flights) opensearch_dashboards_sample_data_ecommerce;"}' -v
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 9200 (#0)
> POST /_plugins/_sql HTTP/1.1
> Host: localhost:9200
> User-Agent: curl/7.64.1
> Accept: */*
> Content-Type: application/json
> Content-Length: 180
> 
* upload completely sent off: 180 out of 180 bytes
< HTTP/1.1 200 OK
< content-type: application/json; charset=UTF-8
< content-length: 214
< 
{
  "error": {
    "reason": "There was internal problem at backend",
    "details": "The following method is not supported in Schema: DAYSOFWEEK",
    "type": "UnsupportedOperationException"
  },
  "status": 500
* Connection #0 to host localhost left intact
}* Closing connection 0

I think the sql engine itself shouldn't return 200 for this, it should be a 400 bad request. Then sql-cli will be able to handle this as TransportError defined in opensearch-py clinet. But since it's 200, sql-cli will assume it's giving data in the format, when it tries to parse it by data['datarows'], an KeyError is thrown.

I can deliver a fix temporarily, while creaing an issue for sql-engine

[zhongnansu]

Created opensearch-project/sql#311