Editor: Update the blocks on the sample page to the latest HTML

[wildworks]

The Sample Page includes updated Quote blocks, so if you open the editor, You'll see a log in your browser console indication the block has been migrated:

Block successfully updated for `core/quote` ({name: 'core/quote', icon: {…}, keywords: Array(2), attributes: {…}, providesContext: {…}, …}).

New content generated by `save` function:

<blockquote class="wp-block-quote"></blockquote>

Content retrieved from post body:

<blockquote class="wp-block-quote"><p>Hi there! I'm a bike messenger by day, aspiring actor by night, and this is my website. I live in Los Angeles, have a great dog named Jack, and I like pi&#241;a coladas. (And gettin' caught in the rain.)</p></blockquote>

Block successfully updated for `core/quote` ({name: 'core/quote', icon: {…}, keywords: Array(2), attributes: {…}, providesContext: {…}, …}).

New content generated by `save` function:

<blockquote class="wp-block-quote"></blockquote>

Content retrieved from post body:

<blockquote class="wp-block-quote"><p>The XYZ Doohickey Company was founded in 1971, and has been providing quality doohickeys to the public ever since. Located in Gotham City, XYZ employs over 2,000 people and does all kinds of awesome things for the Gotham community.</p></blockquote>

We may want to update the block's HTML to avoid this log.

This HTML is in core: ​https://github.com/t-hamano/wordpress-develop/blob/ed2f2ecd3fa043eca3a064a95fcb4830b5c0765c/src/wp-admin/includes/upgrade.php#L313-L339

Trac ticket: https://core.trac.wordpress.org/ticket/63176

[wildworks]

How to test the PR

• Apply the PR to your local env
• Build: npm run build:dev
• Initialize your local env: npm run env:reset, npm run env:start, npm run env:install
• Open your browser console panel
• Access ​http://localhost:8889/wp-admin/post.php?post=2&action=edit
• Confirm that no message is logged

Hi @t-hamano,
I tested the PR according to instructions and the console log statements are gone.

## Latest Trunk:

## This PR:

[abcd95]

Thanks for the PR, @wildworks.

I have tested it according to the instructions provided, and the issue is resolved ✅

[audrasjb]

Hello and thanks for the ticket/patch.

I confirm the patch fixes the issue. When was this markup change introduced in the Quote block? I doubt it was introduced in 6.8 but I'm asking to check whether it has to be fixed in 6.8 or 6.9.

[wildworks]

I think the markup change was introduced by ​https://github.com/WordPress/gutenberg/pull/25892.

It was Gutenberg 13.8, or WordPress 6.1, so there is no need to rush.

[audrasjb]

Alright, thank you!
Let's address this in 6.9 then :)

Before patch:

After patch:
Console is empty.

[audrasjb]

In 60111:

Editor: Update the blocks on the sample page to the latest HTML.

This changeset updates the Quote Blocks HTML markup of the default sample page, to avoid unecessary migration (and the related console information) when loading its content in the editor.

Props wildworks, abcd95, audrasjb, ankitkumarshah.
Fixes #63176.