Description

Similar issue in bedrock/#13770

When ESLint v9.0.0 is released, we should migrate to the new flat config format (which will then be the default). Version 10.0.0 will see the current config format removed.

See: https://eslint.org/blog/2023/10/flat-config-rollout-plans/

Success Criteria

• ESLint config is migrated to the new format