Update find_circuits from Automate to get the flows from /flow_manager/v2/stored_flows

[Gretel Liz]

This issue is to update the related Automate methods to get the flows from /flow_manager/v2/stored_flows.
Also, self._circuits, that used to be updated on every amlight/flow_stats.flows_updated event, will be removed. In the new version, whenever flows are needed, they will be fetched from flow_manager and transformations will be calculated on-the-fly.