consensus: add total vote/commit metrics to measure on-time vs late

[GheisMohammadi]

Adds hmy_consensus_signature_total so we can see how many prepare/commit votes and local commit inclusions were on time vs late. The existing hmy_consensus_late_signature metric is unchanged.

Metrics

Both counters use the same labels: role (leader | validator) and phase (PREPARE | COMMIT | committed).

Metric	Meaning
hmy_consensus_signature_total	All relevant votes/checks: accepted (on time) or late
hmy_consensus_late_signature	Only the late / missing ones

Leader (role=leader, phase=PREPARE or COMMIT)

• Accepted / on time: prepare or commit vote accepted during the current block
• Late: vote for the previous block that arrived after that block was finalized
• Total: accepted + late

Validator (role=validator, phase=committed)

• Accepted / on time: local COMMIT key present in the final COMMITTED bitmap
• Late: local COMMIT key missing from that bitmap
• Total: every local committee key checked in the bitmap

How to calculate

What you want	Formula
Total	hmy_consensus_signature_total
Late	hmy_consensus_late_signature
On time / accepted	signature_total - late_signature
Late rate	late_signature / signature_total
On-time rate	1 - (late_signature / signature_total)

Example PromQL:

# late rate (leader commits)
rate(hmy_consensus_late_signature{role="leader",phase="COMMIT"}[5m])
/
rate(hmy_consensus_signature_total{role="leader",phase="COMMIT"}[5m])

# on-time count
hmy_consensus_signature_total - on(role,phase) hmy_consensus_late_signature

[Frozen]

Just to clarify the intended behavior: if a validator sends one aggregated vote containing 10 BLS keys, signature_total is incremented by 1 rather than 10 here. Is that the expected unit for this metric?