chore: take off filter message push timeouts from message handling metric

[NagyZoltanPeter]

Background

Filter v2 message push timeouts make noise in the waku_filter_handle_message_duration_seconds metric.
It is enough one subscribed peer to disconnect to reach push timeout. So the metric will get +inf bucket filled for the histogram that correlates with the filter errors metric (push timeout).

Details

Acceptance criteria

waku_filter_handle_message_duration_seconds should measure message push durations only for the successful push operations. Consider to separate failing peers pushes from the successful ones. Maybe consider measure an average duration between push to peers inside one event.