Aggregate activity report is slow (and blocking) process with large amount of data

When running the `aggregateActivitiesAndPopulateAggregateCollection` method with a large amount of activity data, the system becomes unresponsive. This seems to be a blocking process.

Determine how to optimize the aggregate activities report method so that it will run faster and not block the main process.

Locate the aggregateActivitiesAndPopulateAggregateCollection method and trace how it processes large activity datasets. Reproduce the unresponsive behavior with a large dataset, then verify that aggregation completes faster without blocking the main process.

Written by the indexing model from the issue text.