Fix bug where empty strings were formatted as undefined by react-final-form (#357)

Author: aatuny

src/frontend/components/common/form/render/RenderEditAdditionalDetails.jsx

@@ -39,6 +39,7 @@ function RenderEditAdditionalDetails({fieldName, label, placeholder}) {
       name={fieldName}
       label={label}
       type="multiline"
+      parse={(v) => v} // identity function for allowing value of ''
       placeholder={placeholder}
     />
   );