Add a metric to display how many peers have pruned your libp2p peer

[shrenujbansal]

User Story

This is a followup from the resolution to #10906
When debugging issues at the libp2p/gossipsub level, we'd like to have more observability into how the outside world is treating your peer. Specifically, a metric to show how many peers have pruned you from their graft would be helpful

Deliverables

By the end of this task, we should have a metric displayed in grafana which shows how many lp2p peers have pruned your peer id per constant time period

Further context available here:
libp2p/specs#555

[rjan90]

Closed as done through: #11058