chore: remove ESLint compatibility code

[9romise]

Since our minimum supported version is currently ESLint 8.57.0.

This PR aligns with the migration guide at https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/, replacing certain APIs that will be removed in ESLint v10 with their modern equivalents.

Related:

• https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/
• https://eslint.org/blog/2025/10/whats-coming-in-eslint-10.0.0/

[changeset-bot]

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Latest commit: b41f03a

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