Allow group and instance-level Jira integrations to set their deployment_type

The Integrations::Jira model only sets the deployment_type for project-level integrations (where #testable? is true). This leads to all instance and group level integration having a deployment_type of unknown because testing is generally disabled for this type of integration.

Instead, we should change the model so group and instance-level Jira integrations will set a deployment_type by removing the #testable? check.