Refactor content viewer components and use for multpart and request body (#333)

src-web/components/core/FormattedError.tsx

@@ -3,12 +3,14 @@ import type { ReactNode } from 'react';
 
 interface Props {
   children: ReactNode;
+  className?: string;
 }
 
-export function FormattedError({ children }: Props) {
+export function FormattedError({ children, className }: Props) {
   return (
     <pre
       className={classNames(
+        className,
         'cursor-text select-auto',
         '[&_*]:cursor-text [&_*]:select-auto',
         'font-mono text-sm w-full bg-surface-highlight p-3 rounded',