Bug: Error after creating task pack with invalid values

[LuckyStrike34R]

Summary

Error after creating task pack with invalid values

Reproduction steps

1. Open https://codebattle.hexlet.io
2. Click on your username on the right side of head
3. Click on "Tasks" button
4. Click on the "Task packs" button
5. Choose "Create new task pack" button
6. Fill the lines: 
Name - space
Visibility - hidden
Task_ids - space
7. Click on "Save" button

Expected result

Сan't create a task pack with invalid data

Actual result

Error page opens

Browsers

Chrome

OS

Windows