Watch: Add unit tests

[Ecarrion]

Descriptions

To favor speed, the watch app was not unit-tested when it was developed.

We should aim to unit test what makes sense to be tested.

Some candidates are:

• [ ] WatchDependenciesSyncronizer
• [ ] PhoneDependenciesSynchronizer
• [ ] WatchTracksProvider
• [ ] MyStoreViewModel
• [ ] OrdersListViewModel
• [ ] OrderDetailLoaderViewModel

[dangermattic]

Thanks for reporting! 👍