update modify space type

[IvanKiral]

Motivation

update modify space type to fit the documentation https://kontent.ai/learn/docs/apis/openapi/management-api-v2/#operation/modify-a-space!path=value&t=request

Checklist

• Code follows coding conventions held in this repo
• Automated tests have been added
• Tests are passing
• Docs have been updated (if applicable)
• Temporary settings (e.g. variables used during development and testing) have been reverted to defaults

How to test

If manual testing is required, what are the steps?

[Enngage]

I would probably use interface (just because it's used within the project :D), but it's okay, thanks! :)