[Typescript-eslint] Fix `@typescript-eslint/no-unused-vars`

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### What is this about?

Fix all errors with `// eslint-disable-next-line @typescript-eslint/no-unused-vars`
Reference: https://typescript-eslint.io/rules/no-unused-vars/

### Scenario

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### Design

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### Technical Details

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### Acceptance Criteria

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### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
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- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
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### References

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Start by locating every `// eslint-disable-next-line @typescript-eslint/no-unused-vars` directive in the repository and read the linked `no-unused-vars` rule documentation. Determine why each reported variable is unused, then run the project's ESLint checks to confirm all such errors are fixed and no new lint failures remain.

Written by the indexing model from the issue text.