fix: parse string schedules in cron update_job() (#10129) (#10521)

update_job() assumed the schedule value was always a pre-parsed dict
and called .get() on it directly.  When the API passes a raw string
like "every 10m", this crashed with AttributeError.

The create path already handles this correctly by calling
parse_schedule() on the incoming string.  The fix adds the same
normalization to the update path: if the schedule is a string,
parse it into a dict before proceeding.

Closes #10129

cron/jobs.py

@@ -501,6 +501,12 @@ def update_job(job_id: str, updates: Dict[str, Any]) -> Optional[Dict[str, Any]]
 
         if schedule_changed:
             updated_schedule = updated["schedule"]
+            # The API may pass schedule as a raw string (e.g. "every 10m")
+            # instead of a pre-parsed dict.  Normalize it the same way
+            # create_job() does so downstream code can call .get() safely.
+            if isinstance(updated_schedule, str):
+                updated_schedule = parse_schedule(updated_schedule)
+                updated["schedule"] = updated_schedule
             updated["schedule_display"] = updates.get(
                 "schedule_display",
                 updated_schedule.get("display", updated.get("schedule_display")),