metric signing_ops_total not incremented by operations not generic

[stephengaudet]

this behaviour exists on v.1.0.0-beta3 and so is not new.

non-generic operations are the baking operations { preendorsement, endorsement, block }
signing of non-generic operations increments metrics vault_sign_request_duration_milliseconds*, but, do not increment the signing_ops_total metric.
only generic operations increment the signing_ops_total metric. sharing the label op = "generic", these operations distinguish themselves with the label "kind" {transfer, reveal, ..etc}
generic operations also increment the metrics vault_sign_request_duration_milliseconds*. when doing so, they do not label for "kind", so, the vault_sign_request_duration_milliseconds* metrics whose op = "generic" do not distinguish themselves by kind like signing_ops_total does.

steps to reproduce:
1.for address XYZ take note of the metrics values
2.do non-generic (baking) operation for address XYZ. observe metrics.
3.do generic (ex: transfer) operation for address XYZ. observe metrics.

expected:
with a name like signing_ops_total, signing any/all operations would update this metric

actual:
baking operations do not update signing_ops_total metric