Fix eslint config: restore .flat accessor for reactHooks.configs

The previous change removed the .flat accessor which caused ESLint to use
the old eslintrc format config (with plugins as array of strings) instead
of the flat config format (with plugins as object). This led to CI failures.

Co-authored-by: d10c <9970661+d10c@users.noreply.github.com>

Author: Copilot

extensions/ql-vscode/eslint.config.mjs

@@ -109,7 +109,7 @@ export default tseslint.config(
     extends: [
       react.configs.flat.recommended,
       react.configs.flat['jsx-runtime'],
-      reactHooks.configs['recommended-latest'],
+      reactHooks.configs.flat['recommended-latest'],
       storybook.configs['flat/recommended'],
       github.getFlatConfigs().react,
     ],
@@ -128,7 +128,7 @@ export default tseslint.config(
     extends: [
       react.configs.flat.recommended,
       react.configs.flat['jsx-runtime'],
-      reactHooks.configs['recommended-latest'],
+      reactHooks.configs.flat['recommended-latest'],
       github.getFlatConfigs().react,
     ],
     settings: {