Issue #3610989: Fix CSV rows misaligning when field content contains a double quote

Lucas Toneattorequested to merge
issue/content_export_csv-3610989:3610989-exported-csv-rows into 8.x-4.x

Replace hand-rolled quote-wrapping and implode()/fwrite() with fputcsv() in ContentExport::getNodeData()/getNodeDataList() and ContentExportForm::submitForm(), so embedded double quotes, commas, and newlines in exported field values are escaped per RFC 4180 instead of breaking column alignment in Excel/Google Sheets.

Closes #3610989

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