[diff] Compare revisions with Split fields layout

Problem/Motivation

#3193231: Add system diff styles is closed, so this issue purely a table cell height issue noticeable on revision page.

Steps to reproduce

1. Install latest Drupal core
2. Download Gin theme and Diff module.composer require drupal/gin drupal/diff
3. Enable Gin and Diff module.
4. Create article and save.
5. Modify article fields and save.
6. Go to revisions and compare last editions, select "Split fields" layout. /node/1/revisions/view/1/2/split_fields

Proposed resolution

Consider overriding Claro theme table td setting:

td {
  height: 4rem;
}

Remaining tasks

User interface changes

Before:

After:

API changes

Data model changes