fix(mongo): Remove aggregate from operations whose arguments get serialized

[lobsterkatie]

Removing aggregate as an operation whose arguments we serialize because pipeline values are complex nested objects which don't serialize well.

aggregate syntax: db.collection.aggregate(pipeline, options)
(see https://docs.mongodb.com/manual/reference/method/db.collection.aggregate/#db.collection.aggregate)

pipeline syntax: [ <stage>, <...> ]
(see https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/)

Example stage syntax: { $match: { <query> } }
(see https://docs.mongodb.com/manual/reference/operator/aggregation/match/ and https://docs.mongodb.com/manual/reference/operator/aggregation/match/#equality-match)

Stages can even end up nested in other stages:

{ $facet:
   {
      <outputField1>: [ <stage1>, <stage2>, ... ],
      <outputField2>: [ <stage1>, <stage2>, ... ],
      ...
   }
}

(see https://docs.mongodb.com/manual/reference/operator/aggregation/facet/ and https://docs.mongodb.com/manual/reference/operator/aggregation/facet/#example)

[github-actions]

size-limit report

Path	Size
@sentry/browser - CDN Bundle (gzipped)	19.73 KB (0%)
@sentry/browser - Webpack	20.6 KB (0%)
@sentry/react - Webpack	20.6 KB (0%)
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	26.88 KB (0%)

[lobsterkatie]

Going to merge this since the broken tests have nothing to do with this change, and will fix the tests separately.