Feature: add showHeader setting

[jonwaldstein]

Description

This adds a simple showHeader settings to the form builder that makes it possible to show or hide the entire header above the form - or in multi-step, the first static step.

Affects

The form builder and donation form.

Visuals

Testing Instructions

• pull branch and run npm run dev
• open a next gen form and use the showHeader settings

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

[jonwaldstein]

@kjohnson this is ready for review.

[kjohnson]

Should the heading, description, and related toggles be show conditionally based on the value of showHeader?

[JasonTheAdams]

I was thinking the same thing, @kjohnson. Perhaps there should be a "Header" group with the show/hide at the top, which toggles the visibility of the other settings?

[jonwaldstein]

@kjohnson this PR has been updated with change to display settings conditionally 0e63ce9