Mint the Sanity document _id for a workflow instance:
<partition>.wf-instance.<suffix>. A bare document ID, never a GDR URI.
Parameters
partition: string
suffix: string = ...
Defaults to a fresh random key, so every call returns a new
id. Pass a suffix derived from the start's own identity to get the same id on
every attempt of that start; it must be a valid document id segment.
Mint the Sanity document
_idfor a workflow instance:<partition>.wf-instance.<suffix>. A bare document ID, never a GDR URI.