Cancel a specific workflow run

Request cancellation of a specific workflow execution identified by its run ID. This is the recommended method for cancelling workflow executions, as it guarantees that only the intended execution is cancelled. Unlike cancelling by workflow ID alone, this avoids a race condition where:

1. A request to cancel the last execution is sent.
2. The last execution completes before the server processes the cancellation.
3. A new workflow execution starts.
4. The server processes the cancellation request and cancels the new execution instead of the intended one.