Describe the feature

similar to #18371

but in addition to the regular notification:

this should also lookup the flashblocks

TODO

• extract the stream await logic to a standalone helper type

that operates on stream of blocks instead, this way we can reuse this logic more easily in op-reth
then specialize this endpoint in the opethapi:

using both the canonstream+ a watch stream over the recent flashblocks

Additional context

No response