Count field proposals, not just tag suggestions, on the Review header

Count field proposals, not just tag suggestions, on the Review header The Review header summed only `row.suggested` (tag suggestions), so a library with alt-text/description proposals but no vocabulary — hence no tag suggestions — read '0 suggestions across 20 assets' while showing 20 assets' worth of field proposals to review. Count fields as well and call them proposals, which is what the page reviews.