fix: countQuery should return a query rather than the pipeline stages

Author: MattLicense

lib/mongoose-aggregate-paginate.js

@@ -142,7 +142,9 @@ function aggregatePaginate(query, options, callback) {
   } else {
     const [pipeline, countPipeline] = constructPipelines();
 
-    const countQuery = options.countQuery ? options.countQuery : countPipeline;
+    const countQuery = options.countQuery
+      ? options.countQuery
+      : this.aggregate(countPipeline);
 
     if (allowDiskUse) {
       countQuery.allowDiskUse(true);