Speed up WorkspacesContentModerationStateTest

Problem/Motivation

Although this is a kernel test it runs 40 tests methods, 5 of which skip after doing a fair bit of setup.

Steps to reproduce

(numbers from my local dev environment)

Before:

Time: 01:00.910, Memory: 6.00 MB

OK, but some tests were skipped!
Tests: 40, Assertions: 2835, Skipped: 5.

After:

Time: 00:55.201, Memory: 6.00 MB

OK, but some tests were skipped!
Tests: 43, Assertions: 2500, Skipped: 8.

There are three more tests skipped and you would expect because of the way that data providers work, confirmed it's the same five methods getting skipped, just we mark one skipped three times instead of once this way.

On gitlab:
Before:

Drupal\Tests\content_moderation\Kernel\WorkspacesContentMode  40 passes  133s 

After:

Drupal\Tests\content_moderation\Kernel\WorkspacesContentMode  43 passes  122s

This isn't saving lots of time, but it's saving a few seconds from what is a very long test for a kernel test (on slower pods it can take a fair bit longer than 130s).

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet