Invalidate Flashblocks when canonical blocks are more recent #51
Description
Currently we only clear Flashblock data when a new Flashblock is received that has a higher block number. We should connect FlashblocksState to the canonical state stream and clear pending Flashblocks when we have a canonical block that has an equal or higher block number.
This will ensure if there's a Flashblocks outage it'll more gracefully degrade to canonical block data.