Fix format conversion utility module syntax

hdyc-svelte/src/lib/utils/formatConversionValue.js

@@ -1,4 +1,4 @@
-function formatConversionValue(value: number | null | undefined): string {
+export function formatConversionValue(value) {
   if (value === null || value === undefined || Number.isNaN(value)) {
     return '—';
   }
@@ -21,4 +21,3 @@ function formatConversionValue(value: number | null | undefined): string {
   const scientific = value.toExponential();
   return scientific.replace(/\.?0+e/, 'e');
 }
-module.exports = { formatConversionValue };