[2025-patches] Drop the use of numpy in Hlt2Conf.lines.rd.builders.strange

Part of LHCb#397

numpy is a relatively heavy import both in terms of time and memory and is not needed in this case (in fact I'd argue numpy/pandas should be banned from the configuration as I struggle to see where they're actually useful).

Note you'll also need LHCb!5173 (merged) to see the effect of this.