MM-45899: Insights: least active channels (#20796)

* Add api endpoints, app layers for top inactive channels with dummy store calls

* Add store functions for top inactive channels

* Add model, store, app tests.

* Add client function and api tests

* Add participants information to TopInactiveChannel

* Translation fix

* Style fix while writing response

* Return channelmember IDs instead of profiles, query in batch avoiding inside the loop

* Make the following changes

 - move DeleteAt to subqueries, to avoid select, group by
 - Remove TeamId from response
 - Count bots and webhook posts

* SQL query lint fix, store test fix to include bot messages

* make app-layers

* Fix empty participant lists being sent as [""]

* Track channel joins, to distinguish 0 activity channels vs new channels

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

store/timerlayer/timerlayer.go

@@ -1653,6 +1653,38 @@ func (s *TimerLayerChannelStore) GetTopChannelsForUserSince(userID string, teamI
 	return result, err
 }
 
+func (s *TimerLayerChannelStore) GetTopInactiveChannelsForTeamSince(teamID string, userID string, since int64, offset int, limit int) (*model.TopInactiveChannelList, error) {
+	start := time.Now()
+
+	result, err := s.ChannelStore.GetTopInactiveChannelsForTeamSince(teamID, userID, since, offset, limit)
+
+	elapsed := float64(time.Since(start)) / float64(time.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetTopInactiveChannelsForTeamSince", success, elapsed)
+	}
+	return result, err
+}
+
+func (s *TimerLayerChannelStore) GetTopInactiveChannelsForUserSince(teamID string, userID string, since int64, offset int, limit int) (*model.TopInactiveChannelList, error) {
+	start := time.Now()
+
+	result, err := s.ChannelStore.GetTopInactiveChannelsForUserSince(teamID, userID, since, offset, limit)
+
+	elapsed := float64(time.Since(start)) / float64(time.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetTopInactiveChannelsForUserSince", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerChannelStore) GroupSyncedChannelCount() (int64, error) {
 	start := time.Now()