It's unclear why you have an "intake probation officer" if your case was dismissed. Perhaps there's now a new case where you are either fighting it or are now on probation for? If a citation was dismissed, it means that you were issued a citation by a law enforcement officer but the case was not pursued by the prosecuting agency.
Where you required to report to probation. On juvenile matters they will sometimes have a juvenile report to probation instead of filing the matter with the court. Oftentimes they will dispose of the case informally by having you do community service etc. You should clarify with the probation department that this refers to the petty theft. The probation officer is in the best position to advise you.
When your matter is referred to probation rather than JV court, they can dismiss your matter or put you on probation and for petty theft would be like stay away from braking the law for one year. In your case apparently PO has dismissed the matter.