foldGutter not working with legacy-mode languages

Here is a basic component that renders fold gutters fine. You can see that I'm importing the language from @codemirror/lang-javascript:

import CodeMirror from "@uiw/react-codemirror";
import { duotoneDark } from "@uiw/codemirror-theme-duotone";

import { javascript } from "@codemirror/lang-javascript";

const text =  `function testFold() {
  // some code
}`

export default function Home() {
  return <CodeMirror
    value={text}
    theme={duotoneDark}
    basicSetup={{
      foldGutter: true,
    }}
    extensions={[javascript()]}
  />
}

However if I try to import it from @codemirror/legacy-modes/mode/javascript I can't see any fold gutter :

import CodeMirror from "@uiw/react-codemirror";
import { duotoneDark } from "@uiw/codemirror-theme-duotone";

import { StreamLanguage } from "@codemirror/language"; // new import
import { javascript } from '@codemirror/legacy-modes/mode/javascript'; // new import
    
const text =  `function testFold() {
  // some code
}`

export default function Home() {
  return <CodeMirror
    value={text}
    theme={duotoneDark}
    basicSetup={{
      foldGutter: true,
    }}
    extensions={[StreamLanguage.define(javascript)]} // using StreamLanguage.define
  />
}

I originally had this issue with the shader mode of the clike legacy-mode language, and unlike javascript I didn't find it elsewhere than in the legacy-mode languages.

Start with the legacy-mode setup using StreamLanguage.define(javascript) in the reported @uiw/react-codemirror example, and compare it with the working @codemirror/lang-javascript setup. Inspect how basicSetup enables foldGutter and how the legacy javascript and clike shader modes expose folding. Done means fold gutters appear for legacy-mode languages, including the reported shader case, with the behavior covered by a regression test.