chore(primitives): remove static file stage

[shekhirin]

Cleanup after #6763

This PR does not remove the StageId::StaticFile variant, as it's unclear whether it's a breaking database change.

check_pipeline_consistency has a strong assumption that the first stage of the pipeline is Headers

reth/crates/consensus/beacon/src/engine/mod.rs

Lines 557 to 598 in 027d50f

	/// Check if the pipeline is consistent (all stages have the checkpoint block numbers no less
	/// than the checkpoint of the first stage).
	///
	/// This will return the pipeline target if:
	/// * the pipeline was interrupted during its previous run
	/// * a new stage was added
	/// * stage data was dropped manually through `reth stage drop ...`
	///
	/// # Returns
	///
	/// A target block hash if the pipeline is inconsistent, otherwise `None`.
	fn check_pipeline_consistency(&self) -> RethResult<Option<B256>> {
	// If no target was provided, check if the stages are congruent - check if the
	// checkpoint of the last stage matches the checkpoint of the first.
	let first_stage_checkpoint = self
	.blockchain
	.get_stage_checkpoint(*StageId::ALL.first().unwrap())?
	.unwrap_or_default()
	.block_number;
	// Skip the first stage as we've already retrieved it and comparing all other checkpoints
	// against it.
	for stage_id in StageId::ALL.iter().skip(1) {
	let stage_checkpoint =
	self.blockchain.get_stage_checkpoint(*stage_id)?.unwrap_or_default().block_number;
	// If the checkpoint of any stage is less than the checkpoint of the first stage,
	// retrieve and return the block hash of the latest header and use it as the target.
	if stage_checkpoint < first_stage_checkpoint {
	debug!(
	target: "consensus::engine",
	first_stage_checkpoint,
	inconsistent_stage_id = %stage_id,
	inconsistent_stage_checkpoint = stage_checkpoint,
	"Pipeline sync progress is inconsistent"
	);
	return Ok(self.blockchain.block_hash(first_stage_checkpoint)?)
	}
	}
	Ok(None)
	}

But because we had StaticFile as the first stage without an actual stage implementation, its checkpoint was always zero, so the consistency check passed, and the node went to live sync instead of continuing the pipeline sync.