refactor: comment out unused import in drop-test-tables and add biome configuration

[Artuomka]

No description provided.

[Copilot]

Pull request overview

This PR performs refactoring to align the test utilities with linting standards by commenting out an unused import and adding a Biome configuration file specifically for the test directory.

Changes:

• Commented out unused getTestKnex import in drop-test-tables.ts to fix linting warnings
• Added backend/test/biome.json configuration extending the root config with relaxed rules for test code

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
backend/test/utils/drop-test-tables.ts	Commented out unused import that was only referenced in already-commented implementation code
backend/test/biome.json	New Biome linter configuration for test directory that extends root config and disables rules commonly problematic in test code (unused variables, explicit any, etc.)

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