Report state transition number for workflows

[mikhailshilkov]

Is your feature request related to a problem? Please describe.
I want to evaluate a "complexity" metric of a workflow execution - how much load burden it puts on the Temporal server. See temporalio/maru#4 for context.

Describe the solution you'd like
Temporal server should add this counting feature to the history service. So every workflow should return the number of state transitions it used and include it into the visibility record on close.

[samarabbas]

@mikhailshilkov @alexshtin I thought we already added support for reporting state transitions both as metric and visibility records. Can this issue be closed now?

[alexshtin]

Yes, this field is added to workflow mutable state and also to advanced visibility.