Search block: Add space between attributes

[sabernhardt]

What?

Attributes in the expandable Search block start tag need to be separated.

Why?

Without spaces, the HTML does not pass validation.

How?

In addition to spaces, this includes line breaks around $form_context so the attributes are indented the same.

Screenshots or screencast

Invalid output in WordPress 6.5 (no plugins):

<div class="wp-block-group is-content-justification-left is-layout-flex wp-container-core-group-is-layout-3 wp-block-group-is-layout-flex"><form role="search" method="get" action="http://localhost/wp65/" class="wp-block-search__button-only wp-block-search__searchfield-hidden wp-block-search__text-button wp-block-search" 
		 data-wp-interactive="core/search"data-wp-context='{"isSearchInputVisible":false,"inputId":"wp-block-search__input-1","ariaLabelExpanded":"Submit Search","ariaLabelCollapsed":"Expand search field"}'data-wp-class--wp-block-search__searchfield-hidden="!context.isSearchInputVisible"
		 data-wp-on--keydown="actions.handleSearchKeydown"
		 data-wp-on--focusout="actions.handleSearchFocusout"
		>

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Co-authored-by: sabernhardt <sabernhardt@git.wordpress.org>
Co-authored-by: carolinan <poena@git.wordpress.org>

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[sabernhardt]

Related: #58943

[carolinan]

Hi
Can you include testing instructions for this PR? The code change looks valid to me, but I could not figure out where this markup is used.
I added the search block to a post, but it does not have these data attributes.

[sabernhardt]

Thanks for adding the labels.

Steps:

1. Open the editor (either site or post).
2. Add a Search block.
3. Choose the "Button only" option from the block toolbar.
4. Save changes.
5. View the post or site template on the front end, and view source to find the missing spaces.
6. Apply the PR changes.
7. Refresh the page and view source to verify that data-wp- attributes have space between them.
8. Verify that the Search block still functions the same way (expanding the input and submitting search query).