add db aggregate

Author: qingyang-hu

source/crud/tests/unified/db-aggregate-rawdata.json

@@ -29,15 +29,13 @@ tests:
             - { $limit: 1 }
             - { $addFields: { dummy: 'dummy field' } }
             - { $project: { _id: 0, dummy: 1 } }
-          rawData: &rawdata true
     expectEvents:
       - client: *client0
         events:
           - commandStartedEvent:
               command:
                 aggregate: 1
                 pipeline: *pipeline
-                rawData: *rawdata
   - description: "Aggregate with rawData option on less than 8.2.0 - ignore argument"
     runOnRequirements:
       - maxServerVersion: "8.1.99"