Materialized view referencing current date/time not refreshed when underlying tables did not change

[findepi]

reproducible with io.trino.plugin.iceberg.IcebergQueryRunner.DefaultIcebergQueryRunnerMain#main

CREATE MATERIALIZED VIEW mv GRACE PERIOD INTERVAL '3' SECOND AS SELECT CURRENT_TIMESTAMP t FROM nation WHERE nationkey=1;

REFRESH MATERIALIZED VIEW mv;

TABLE mv;
                   t
---------------------------------------
 2024-06-27 21:25:54.269 Europe/Warsaw

now, when user waits a few seconds and queries the MV again, they can expect a timestamp not older than current time - 3 seconds, but that's not the case

TABLE mv;
                   t
---------------------------------------
 2024-06-27 21:25:54.269 Europe/Warsaw

[findepi]

cc @alexjo2144 @marton-bod @sopel39