graph/db: expose reset in ForEachChannel

Add a `reset` call-back param to the V1Store ForEachChannel method.

graph/db/sql_store.go

@@ -1343,9 +1343,7 @@ func (s *SQLStore) ForEachChannelCacheable(cb func(*models.CachedEdgeInfo,
 // NOTE: part of the V1Store interface.
 func (s *SQLStore) ForEachChannel(ctx context.Context,
 	cb func(*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
-		*models.ChannelEdgePolicy) error) error {
-
-	reset := func() {}
+		*models.ChannelEdgePolicy) error, reset func()) error {
 
 	handleChannel := func(db SQLQueries,
 		row sqlc.ListChannelsWithPoliciesPaginatedRow) error {