Describe the feature

we should do similar thing here as we do in sparse trie updates

[https://github.com/paradigmxyz/reth/blob/e9598ba5ac4e32600e48b93d197a25603b1c644b/crates/engine/tree/src/tree/payload_processor/sparse_trie.rs#L[…]6](

basically drain the channel, aggregate everything, and then batch

Additional context

In MultiProofTask::run, mirror the sparse trie pattern
reth/crates/engine/tree/src/tree/payload_processor/sparse_trie.rs

by draining additional PrefetchProofs / StateUpdate messages with try_recv and merging their targets before handing them to the manager. Current handling without draining:

reth/crates/engine/tree/src/tree/payload_processor/multiproof.rs