[BUG] JSON format throw exception on legacy engine.

Describe the bug
A clear and concise description of what the bug is.

To Reproduce

PUT /test-00001?pretty 
{
  "settings": {
    "number_of_shards": 1
  },
  "mappings": {
    "properties": {
      "day": { "type": "date" },
      "region": { "type": "keyword" },
      "host": { "type": "keyword" },
      "errors": { "type": "integer" }      
    }
  }
}

PUT /_bulk
{ "index" : { "_index" : "test-00001", "_id" : "1" } }
{ "day": "2021-01-03", "region": "iad", "host": "h1", "errors": 2}
{ "index" : { "_index" : "test-00001", "_id" : "2"} }
{ "day": "2021-01-03", "region": "iad", "host": "h2", "errors": 3}

### Success
POST /_plugins/_sql
{
  "query": "SELECT * FROM issue-395 WHERE lower(region) LIKE '%iad%'"
}

### Exception
POST /_plugins/_sql?format=json
{
  "query": "SELECT * FROM issue-395 WHERE lower(region) LIKE '%iad%'"
}

Expected behavior
https://github.com/opensearch-project/sql/blob/main/docs/user/interfaces/protocol.rst#opensearch-dsl

Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

Start by reproducing the request in the issue against the legacy engine, then read the linked protocol.rst OpenSearch DSL section to confirm the expected JSON behavior. Done means the same SQL query with format=json returns a valid response instead of throwing an exception; the issue does not name a source file or test to update.