Add metric to record the number of aggregated log records

[MikeGoldsmith]

Component(s)

processor/logdedup

Is your feature request related to a problem? Please describe.

It would be useful to have a metric to record the number of deduplicated logs.

Describe the solution you'd like

Add a metric to track the number of deduplicated log records.

Describe alternatives you've considered

No response

Additional context

No response

[github-actions]

Pinging code owners for processor/logdedup: @BinaryFissionGames @MikeGoldsmith @djaglowski. See Adding Labels via Comments if you do not have permissions to add labels yourself.

[crobert-1]

Removing needs triage as this was filed by a code owner, and makes sense to me.