Upgrade ESLint to version 9

[luisaveiro]

Purpose

This pull request upgrades the ESLint dependency from its previous version to version 9. This upgrade includes:

Switch to use ESLint flat config.
Switch to Prettier config.js format.

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Related Issue

Please link to the issue/discussion here: N/A

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Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).
• Refactoring.
• Other (config, documentation).

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Are breaking changes introduced?

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How Has This Been Tested?

• Changes are covered by existing tests.
• Changes are covered by new tests.
• Changes are not covered by tests.

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Development Checklist

• My code follows our coding standards.
• All new and existing tests passed.
• I have read the CONTRIBUTING document.
• I have updated the CHANGELOG accordingly.
• I have updated the README, if necessary.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud