adacam-odc: fix purge table name (landmarks not detections)

services/adacam-odc/adacam_odc.py

@@ -773,7 +773,7 @@ def purge_forwarded_detections():
         conn.row_factory = sqlite3.Row
         cur = conn.cursor()
         cur.execute(
-            "DELETE FROM detections WHERE id <= ? AND ts < ?",
+            "DELETE FROM landmarks WHERE id <= ? AND ts < ?",
             (cursor_id, cutoff_ms)
         )
         deleted = cur.rowcount