* chore: add test expectations for integration metrics connection status
* chore: reorg logs connection status calculation for parallelization
* chore: add interface for reader.GetMetricLastReceivedTsMillis
* chore: add plumbing for calculating integration metrics connection status
* chore: impl and test mocks for reader.GetMetricReceivedLatest
* chore: wrap things up and get test passing
* chore: some cleanup
* chore: some more cleanup
* chore: use prom metric names for integration connection test