[MB-37744] Behavior for query request max_parallelism different from documented behavior

The max-parallelism setting for query request is not working as it is documented. Below are the steps to reproduce this.

1. Set server level max_parallelism setting to default value which is 1.
2. Execute query using REST API call to query server:

curl http://<query_server>:8093/query/service -u <username>:<password> -d 'statement=SELECT * from `beer-sample` WHERE country ="India" limit 1;&max_parallelism=3'

On executing the above query we see that query uses 3 cores. However, according to our documentation about Request-Level :

If a request includes max_parallelism, it will be capped by the server max-parallelism.

The same behavior can be observed from UI as well:

1. Set Server level max_parallelism to 1.
2. Set Query level max_parallelism to 3.
3. Execute the query and see the PLAN TEXT.
4. Search for field called "copies", we see 3 copies.

Reproduction