[export] use a rolling date on age aggregator (Person)

This query allow to detects the saved export which won't work any more:

```sql
select
s.id, user_id, description, title, u.label
from chill_main_saved_export s join users u on u.id = s.user_id
WHERE
options->'export'->'export'->'aggregators'->'person_age_aggregator'->'enabled' is not null;
```

.changes/unreleased/Fixed-20230629-231503.yaml

@@ -0,0 +1,5 @@
+kind: Fixed
+body: '[export] set rolling date on person age aggregator'
+time: 2023-06-29T23:15:03.20841309+02:00
+custom:
+  Issue: ""