Make node exit future independent of error receiver

[mattsse]

Describe the feature

reth/crates/node-core/src/exit.rs

Lines 12 to 17 in 270df3e

	/// A Future which resolves when the node exits
	#[derive(Debug)]
	pub struct NodeExitFuture {
	/// The receiver half of the channel for the consensus engine.
	/// This can be used to wait for the consensus engine to exit.
	consensus_engine_rx: Option<oneshot::Receiver<Result<(), BeaconConsensusEngineError>>>,

TODO

• replace oneshot::Receiver<Result<(), BeaconConsensusEngineError>> with a boxed future that returns eyre::Result<()> or result with boxed error

Additional context

No response

[greged93]

Hey @mattsse can I try this one?