Default height for empty paragraphs in rich-text editor

[falkodev]

Summary

Blank lines respected in CMS rich text editor
https://linear.app/apostrophecms/issue/PRO-4526/blank-spacing-not-being-respected-in-cms-rich-text-editor

Edit mode:

Preview mode:

What are the specific steps to test this change?

1. Run the website and log in
2. Edit a rich-text editor, add new lines by hitting the button "Enter". Publish changes.
3. Go in preview mode and check the new lines are respected out of the edit mode
4. Log out and check new lines are still present

What kind of change does this PR introduce?

• Bug fix
• New feature
• Refactor
• Documentation
• Build-related changes
• Other

Make sure the PR fulfills these requirements:

• It includes a) the existing issue ID being resolved, b) a convincing reason for adding this feature, or c) a clear description of the bug it resolves
• The changelog is updated
• Related documentation has been updated
• Related tests have been updated

[linear]

PRO-4526 Blank spacing not being respected in CMS rich text editor

Overview

When using the rich text editor, and trying to add line breaks, those line breaks are not respected in Preview. That makes for a difficult/weird editing experience.

From iCIMS specifically:

BMS added spaces in their rich text, when previewed or published this space is treated as nothing. As a workaround I have added periods that match the page background color.

Page: https://bms.cms.talentplatform.us/blog/immunology-careers-at-bms-numerous-paths-one-patient-centered-mission

Prod page: https://careers.bms.com/blog/immunology-careers-at-bms-numerous-paths-one-patient-centered-mission

From BMS:

When I published the article below, I included paragraph returns in between each paragraph. These spaces show in the editor but not in preview. In production all of the paragraphs are closely stacked on top of each other with no vertical spacing. I've attached screenshots of production and of the article page in the CMS.

Recording: Screen Recording 2023-07-13 at 12.19.17 AM.mov

The rich text editor does not respect spaces or "returns" when previewed. Starting a new paragraph and adding a empty line between paragraphs has the same outcome.

Acceptance Criteria

When using the rich text editor in A3, and adding a line break, I should see that space reflected in Preview.

NOTE: See the linked ticket for information on this regression.