Missing scopes when parsing <script> with custom parser

[fnx]

Before You File a Bug Report Please Confirm You Have Done The Following...

• I'm using eslint-plugin-vue.
• I'm sure the problem is a parser problem. (If you are not sure, search for the issue in eslint-plugin-vue repo and open the issue in eslint-plugin-vue repo if there is no solution.
• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.

What version of ESLint are you using?

8.57.0

What version of eslint-plugin-vue and vue-eslint-parser are you using?

• vue-eslint-parser@9.4.2
• eslint-plugin-vue: irrelevant

What did you do?

Configuration

import * as vue from 'vue-eslint-parser';

export default [{
	languageOptions: {
		parser: vue,
		parserOptions: { parser: { ts: '@typescript-eslint/parser' } }
	}
}]

<script setup lang="ts">
function fn() {}
</script>

What did you expect to happen?

There is a child scope for the function declaration nested in the module scope.

What actually happened?

The module scope has no child scopes.

Link to Minimal Reproducible Example

https://github.com/DMartens/vue-eslint-parser-script-custom-parser-scope

Additional comments

This only happens when using a custom parser via the lang attribute.