[5.x]: Field validation on required fields doesn't work when enabling entry for different site

[WHITE-developer]

What happened?

Description

Steps to reproduce

1. Create a new entry that has a few required fields (other than the title, which is always required).
2. Give the entry a title, but do not put any value in the other required fields
3. You are able to create the entry when the entry is still disabled, so there is no validation, but this is fine
4. When you are editing the entry on, for example, English and choose to enable the entry for another language (see screen below) you are able to save the entry and there is no validation on this entry for the other site.
   

Expected behavior

You cant save and enable the entry, because the required fields, on the other site that is enabled, are not filled in.

Actual behavior

Craft CMS version

5.4.4

PHP version

No response

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

[i-just]

Hi, thanks for reporting! I raised a PR for this.