test(integrations/import): align fixture to ESLint ^9

[2nofa11]

Update tests/integrations/eslint-plugin-import/package.json to use ESLint ^9 (or ^8) and eslint-plugin-import ^2.31.0, matching the plugin’s peerDependencies (^8 || ^9).
Test-only; no user-facing changes.

closed #2930
Linked to: #2916

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Latest commit: 124c58f

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[FloEdelmann]

Thanks, looks good to me 🙂

[Copilot]

Pull Request Overview

Updates the ESLint plugin import integration test to use ESLint version 9 and migrates from the legacy .eslintrc.json configuration format to the new flat config format (eslint.config.mjs).

• Upgrades ESLint from ^7.0.0 to ^9.0.0 and eslint-plugin-import from ~2.23.4 to ^2.31.0
• Migrates from legacy .eslintrc.json to flat config eslint.config.mjs format
• Updates test execution to use the new configuration file

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tests/integrations/eslint-plugin-import/package.json	Updates ESLint and eslint-plugin-import versions
tests/integrations/eslint-plugin-import/eslint.config.mjs	Adds new flat config format configuration
tests/integrations/eslint-plugin-import/.eslintrc.json	Removes legacy configuration file
tests/integrations/eslint-plugin-import.js	Updates test to use new config file

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