IMPROVE - Add test coverage for OdometerViewModel

[lauriecai]

Describe the feature you want to improve

Test CRUD operations for OdometerViewModel - including initial state, add/delete/get/update readings, and get vehicles

[shilwantk]

@mikaelacaron I would like to work on this issue.

[mikaelacaron]

@shilwantk there's no need for this issue because it has an open PR, I just haven't gotten around to viewing it

if you could pick a different issue, that would be great! thanks for wanting to contribute! I want to come back to this project and be more active last this year