Bug: User can set blank nickname through API

[Dmitrydrum]

Summary

User can set empty nickname through API by postman.
Current version: babf5ed
Prerequisites:
Set cookie and x-srf-token in postman
endpoint https://codebattle.hexlet.io/api/v1/settings

Reproduction steps

1. Type https://codebattle.hexlet.io/api/v1/settings in url
2. Select "PATCH" method
3. Type json in body "name": ""
4. Click on "send" button

Expected result

Validation error. Nickname doesn't change.

Actual result

Nickname changes to empty string

Browsers

No response

OS

No response