Convert ckEditor5EditorHeightTest to WebDriver test

Problem/Motivation

We are trying to deprecate node_add_body_field in 📌 Deprecate node_add_body_field() Active but currently NodeTypeForm is calling this for the testing profile (since 📌 Remove node_add_body_field from NodeTypeForm Active ) just for these Nightwatch tests.

In 📌 Consider dropping Nightwatch in favor of Functional Javascript tests Active I think we all agree that Nightwatch is unreliable, and looking at the tests they are doing an awful lot of costly operations via the UI that if it were a PHP test we could use API to do for us (install the site, install modules, set up content types, etc).

Instead of adding even more UI clunk to Nightwatch in order to setup a body field, let's just convert these to WebDriver tests. There's nothing in there that can't be done in PHP afaict.

Proposed resolution

Convert ckEditor5EditorHeightTest to a WebDriver test.

Remaining tasks

Do it