Expected Excel output not shown

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When ran on national node level, output of analytical pipeline is not just the HTML files, but also Excel files like results-survival-analysis-ESP.xlsx -- these are not shown in this baseline use case

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I've added a minimal description to the RO-Crate metadata file as the excel file was already there in outputs, but uncertain how it was made and its columns

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#4 from @MarjanMeurisse added the excel generation in step 6 https://github.com/by-covid/BY-COVID_WP5_T5.2_baseline-use-case/blob/main/vaccine_effectiveness_analytical_pipeline/scripts/6_survival-analysis.QMD so we need to just wire this into the provenance RO-Crate wise.