Add Test cases for model classes. Fixes T865

Summary:
 - Add tests for `DeploymentModel` class
 - Add tests for `DeploymentModelDataMapper` class

Test Plan:
At the root of the project
 - Run `./gradlew :app:connectedAndroidTest`

Reviewers: PapaLee, dkobia

Subscribers: shadowhand, rjmackay

Maniphest Tasks: T865

Differential Revision: https://phabricator.ushahidi.com/D417