Ensure that RAW only applies to queries with a single projection

Currently, we nievely add RAW to every COUNT function, which means queries like this fail because its a SQL++ syntax error:

SELECT `c`.`EnrollmentDate` as `EnrollmentDate`, RAW COUNT(*) as `StudentCount`

FROM `contoso`.`person`.`person` AS `c`

WHERE `c`.`Discriminator` = "Student"

GROUP BY `c`.`EnrollmentDate`

We only want to add RAW for queries that look like this:

SELECT COUNT(*)

FROM `contoso`.`person`.`person` AS `c`

WHERE `c`.`Discriminator` = "Student"

Which results in:

[

  {

    "$1": 8

  }

]

If RAW is added to the query, then the output will look like:

[

  8

]

The alternative is to detect the nesting on deserialization and treat it as a scalar value.