Fix: Last Owner is not able to be deleted (coscine/issues#251)

coscine/issues#251

src/Project/Controllers/ProjectRoleController.cs

@@ -85,6 +85,8 @@ namespace Coscine.Api.Project.Controllers
                 ProjectModel projectModel = new ProjectModel();
                 if (projectModel.OwnsProject(user, projectModel.GetById(projectId)))
                 {
+                    _projectRoleModel.CheckIfLastOwnerWillBeRemoved(roleId, projectId);
+
                     return _projectRoleModel.Delete(_projectRoleModel.GetWhere((projectRole) =>
                             projectRole.ProjectId == projectId
                             && projectRole.UserId == userId