Closes #2542 - fix test and comments

Author: mmenv

lib/taskana-core/src/main/java/pro/taskana/task/internal/TaskCommentServiceImpl.java

@@ -13,7 +13,6 @@
 import pro.taskana.task.api.exceptions.NotAuthorizedOnTaskCommentException;
 import pro.taskana.task.api.exceptions.TaskCommentNotFoundException;
 import pro.taskana.task.api.exceptions.TaskNotFoundException;
-import pro.taskana.task.api.models.Task;
 import pro.taskana.task.api.models.TaskComment;
 import pro.taskana.task.internal.models.TaskCommentImpl;
 import pro.taskana.user.api.models.User;