import: handle unrecognized workbook rows #993

Current situation

When the importer can't match a workbook row to a pathway, it skips that row and lists it at the end of the report. The rest of the import still goes ahead.

Problem

That makes it easy to miss a pathway. A typo in the abbreviation, or a pathway the importer hasn't been set up for yet, means the row is quietly left out. This week, 11 rows were skipped because they hadn't been set up yet.

Options

• Keep it as it is. Skipped rows are only listed in the report. This works well when the workbook includes pathways that aren't ready to import yet.
• Stop the import when any row isn't recognised. Nothing gets missed, but every row in the workbook has to be set up in the importer first.

Both options assume new pathways still have to be set up in the importer by hand. Whether that step can go away is tracked in #994. If it does, far fewer rows would go unrecognised, so this decision becomes less important.

Raised in review of #992.