Call VerifyStateTransition in Reduction 2 only if it is a committee member

[goshawk-3]

Describe the bug
Current implementation calls VST immediately after reaching quorum at reduction 1. However, VST is supposed to be called prior to voting (as prerequisite) at reduction 2, only if the provisioner is committee member.

To Reproduce
Run a cluster with a node that does not stake. This node will always call VST without participating in consensus ever.

Additional context
This is issue should not be confused with the one for adding VST call in reduction 1.