Update classes for custom typography

[laurelfulford]

All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

In Gutenberg 7.9, how some classes were applied in the editor has changed, which has broken some of the custom typography.

This PR fixes that in the parent theme's custom typography code. If there are issues in the child themes, I'll address them in seperate PRs.

This PR also includes a fix for fonts on the front end for the categories, archives and file blocks.

Lastly, there's some pretty gnarly issues with the button block as of 7.9 that I'll be addressing separately; only that block's custom typography in the editor needs to be checked with this PR.

See #893.

How to test the changes in this Pull Request:

1. Copy-paste the following content into a page: https://cloudup.com/cEUOHTlPNza -- it includes a selection of blocks and settings that have been updated.
2. For the Homepage Posts block, add a subtitle to at least one of the posts that display there.
3. Navigate to Customize > Typography, and pick very noticeably different fonts.
4. View your page in the editor, and the post you added a subtitle to; note a lot of things aren't picking up the custom fonts, or if they are, they're picking up the wrong ones (like the headers inheriting the body font).
5. Apply the PR.
6. Confirm that the blocks are using the proper fonts.

In my examples, the titles should be using Impact, and the body should be using Chalkboard -- specific blocks I noticed issues with, include:

Post/Page title:

Before - using the theme default:

After:

Header Blocks

Before - using the body font:

After:

Table block:

Before - using theme's default body font:

After:

Button Block:

Before - using body font:

After:

Homepage Posts block:

Before - entry meta using theme's default:

After:

Subtitle (on single post):

Before - using theme's default body font:

After:

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?

[laurelfulford]

It looks like the post title class change was introduced in Gutenberg 7.9.1: WordPress/gutenberg#21099

I'm less sure about the header block, or table.

[laurelfulford]

Thanks Jeff!

[matticbot]

🎉 This PR is included in version 1.6.1 🎉

The release is available on GitHub release

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