Fix workflow ID reference in Send function to use current workflow state

[af-md]

No description provided.

[maxdml]

Good catch! You are right, Send() from a workflow should check that its own ID has already executed.

We should also add a test for this case in the TestSendReceive suite. Generally speaking the suite doesn't test that Send is idempotent. The "idempotency test" in SendRecvSuccess gets the recorded result of the workflow, not step by step..

Could you add that to the PR as well 🙏? (In other tests you can find the logic that blocks a workflow artificially so that we can invoke it again with the same ID and check steps idempotency. After both invocation executes, GetWorkflowSteps should return the expected number of steps)

(we should do the idempotency test for Recv() as well. Both send and recv are special steps)