[Spike] Improve unit test coverage: Phase 1

[JunTaoLuo]

This issue tracks part of the unit test improvement work identified in https://github.com/department-of-veterans-affairs/va.gov-team/issues/89844.

Phase 1 will involve steps:

• Run the coverage tool: yarn test:coverage-app --app-folder vaos
• Identify files sources with < 80% branches coverage
• File individual tickets to add unit tests for the identified files

Definition of Done

• [ ] Engineering tickets filed for all source files with < 80% branches coverage

[Bren22va]

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