Eliminate redundant partition stats update

The update_partition_stats_q function is being invoked from load_partition in the pypgstac. However, this function is also being automatically triggered by changes to the items table:

postgis=> \dS items;
...
Triggers:
    items_after_delete_trigger AFTER UPDATE ON items REFERENCING NEW TABLE AS newdata FOR EACH STATEMENT EXECUTE FUNCTION partition_after_triggerfunc()
    items_after_insert_trigger AFTER INSERT ON items REFERENCING NEW TABLE AS newdata FOR EACH STATEMENT EXECUTE FUNCTION partition_after_triggerfunc()
    items_after_update_trigger AFTER DELETE ON items REFERENCING OLD TABLE AS newdata FOR EACH STATEMENT EXECUTE FUNCTION partition_after_triggerfunc()

Reference to the trigger definitions.

Is this redundant? If so, we should consider removing the redundant call from load_partition.

Start in src/pypgstac/python/pypgstac/load.py around load_partition and compare its update_partition_stats_q call with the trigger definitions in src/pgstac/sql/003a_items.sql. Trace whether the items-table triggers already perform the same update, then confirm the intended behavior and identify any relevant existing checks before removing a duplicate call. Done means partition statistics are updated once without changing load behavior.