Implement GoPgo.AggregateCallees outside of merges if possible #4424
Description
When fetching pprof for PGO purposes via SelectMergeProfile, an option can be passed to aggregate callees:
pyroscope/api/types/v1/types.proto
Line 101 in b1614a0
The way this is implemented right now relies on the aggregation happening during profile merges, however we could have cases where profiles are returned as they are (without merging). See if we can implement this in an alternative way.
Related to #4421