builders: fix readonly value

Components/Calculation/builders/build-readonly.tsx

@@ -14,7 +14,7 @@ export default function buildReadonly(
   { elementName, valueName }: BuilderProps
 ) {
   return observer<ElementsProps[typeof elementName]>((props) => {
-    const value = useValue(valueName);
+    const [value] = useValue(valueName);
 
     return <Component value={value} readOnly {...props} />;
   });