ExtraSampleAttrProd reporter config can no longer be used externally

[athre0z]

The following config:

opentelemetry-ebpf-profiler/reporter/config.go

Line 59 in aea5a17

ExtraSampleAttrProd samples.SampleAttrProducer

Can no longer be set by agent-as-a-library consumers, because the samples package that contains various helper types that are needed to implement the SampleAttrProducer interface were moved to an internal package during #245.

CC @dmathieu

Edit: I'll have to read into the new collector reporter impl.. maybe this functionality isn't required anymore, and equivalent functionality can be achieved without this interface?