Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[x] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofix to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

Tell us about your environment (npx eslint --env-info):

• Node version: latest
• npm version: latest
• Local ESLint version: latest
• Global ESLint version: latest
• Operating System: windows

What parser are you using (place an "X" next to just one item)?

[x] Default (Espree)
[ ] @typescript-eslint/parser
[ ] @babel/eslint-parser
[ ] vue-eslint-parser
[ ] @angular-eslint/template-parser
[ ] Other

Please show your full configuration:

// eslint.config.js
export default [
  {
    rules: {
      "no-useless-assignment": "warn"
    },
  },
];

What did you do? Please include the actual source code causing the issue.\

async function fn() {
  let intermediaryValue;
  try {
    intermediaryValue = 42;
    unsafeFn();
    return { error: undefined };
  } catch {
    return { intermediaryValue };
  }
}

function unsafeFn() {
  throw new Error();
}

What did you expect to happen?
intermediaryValue won't get reported as it is used in catch block.

What actually happened? Please include the actual, raw output from ESLint.
it reports the intermediaryValue as unused variable.

Is there anything you'd like reviewers to focus on?

fixes #19245