### Description

This is to investigate what we could do to support the data streams in SQL. The backing indices can be queried already, but to address them similarly as they're queried over QDSL one would need to construct a pattern learned out of band and not through SQL metadata discovery mechanisms.
x-pack/plugin/sql/qa/server/src/main/java/org/elasticsearch/xpack/sql/qa/rest/RestSqlTestCase.java
expected = """
                {"columns":[{"name":"test1","type":"text"}],"rows":[["test1"],["test2"]]}""";
        }
        executeAndAssertPrettyPrinting(expected, randomFrom("false", null), columnar);
    }
    private void executeAndAssertPrettyPrinting(String expectedJson, String prettyParameter, boolean columnar) throws IOException {
        index("{\"test1\":\"test1\"}", "{\"test1\":\"test2\"}");
        Request request = new Request("POST", SQL_QUERY_REST_ENDPOINT);
        if (prettyParameter != null) {
            request.addParameter("pretty", prettyParameter);
        }
        if (randomBoolean()) {
            
            request.addParameter("format", "json");
        }
        if (randomBoolean()) {
            
            RequestOptions.Builder options = request.getOptions().toBuilder();
            options.addHeader("Accept", randomFrom("*/*", "application/json"));
            request.setOptions(options);
        }
        request.setEntity(
            new StringEntity(
                query("SELECT * FROM " + indexPattern("test")).mode(Mode.PLAIN).columnar(columnarValue(columnar)).toString(),
                ContentType.APPLICATION_JSON
            )
        );
        Response response = client().performRequest(request);
        try (InputStream content = response.getEntity().getContent()) {
            String actualJson = new BytesArray(content.readAllBytes()).utf8ToString();