app: Avoid creating empty ingredient

app/src/ingredients.rs

@@ -297,6 +297,10 @@ pub fn Ingredients() -> Html {
             .expect("editIgUnit is not an input element");
         let unit = unit_elem.value();
 
+        if name.is_empty() && unit.is_empty() {
+            return;
+        }
+
         let token = token.clone();
         let err = err.clone();
         let render = render.clone();