The requested assigneeId does not hold a skill required by the task's
category (code: ASSIGNEE_MISSING_REQUIRED_SKILL). Only returned when the
organization restricts task assignment OR task visibility to matching skills,
AND the task's category is linked to a skill. A user holding that skill under EITHER
auto-assign or manual-only is accepted; only a user holding it under neither
is refused. Re-sending a task's existing assignee is always allowed, so a
status-only update never returns this.