Replace go-migrate with morph (#19116)

store/timerlayer/timerlayer.go

@@ -1726,22 +1726,6 @@ func (s *TimerLayerChannelStore) MigrateChannelMembers(fromChannelID string, fro
 	return result, err
 }
 
-func (s *TimerLayerChannelStore) MigratePublicChannels() error {
-	start := timemodule.Now()
-
-	err := s.ChannelStore.MigratePublicChannels()
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.MigratePublicChannels", success, elapsed)
-	}
-	return err
-}
-
 func (s *TimerLayerChannelStore) PermanentDelete(channelID string) error {
 	start := timemodule.Now()