Query Title: Add "Post Type Label" variation

[BugReportOnWeb]

What?

Closes #55949

This PR adds a "Post Type Label" variation to the core/query-title block, which displays the singular name of the queried post type.

Why?

Currently, there’s no way to dynamically display the post type label in a query context. This variation extends core/query-title to support built-in and custom post types.

How?

• Added new variation "Post Type Label" to display the queried post type's singular name.
• Retrieves the post type from block context or default to the current post type.

Testing Instructions

1. Add multiple Query Loop blocks.
2. Change query settings and configure for different post types (posts, pages, custom post types).
3. Add a 'Post Type Label' block inside the Query Loop block.
4. Test the setting for displaying the Post Type prefix.
5. Save the post and check the frontend.
6. Confirm that post type labels are rendered correctly in both the editor and frontend.

Screenshots or screencast

Using "Post Type Label" under each post title to show the queried post type (with and without prefix).

[github-actions]

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Co-authored-by: BugReportOnWeb <[email protected]>
Co-authored-by: ryanwelcher <[email protected]>
Co-authored-by: t-hamano <[email protected]>
Co-authored-by: bhubbard <[email protected]>

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[ryanwelcher]

Can we import the store name here instead of suppressing the eslint error?

[BugReportOnWeb]

Thank you for the review!

I did this to avoid having @wordpress/editor as a dependency for @wordpress/block-editor. A similar pattern is used in useArchiveLabel:

gutenberg/packages/block-library/src/query-title/use-archive-label.js

Lines 9 to 16 in 4ad8b27

	// @wordpress/block-library should not depend on @wordpress/editor.
	// Blocks can be loaded into a *non-post* block editor, so to avoid
	// declaring @wordpress/editor as a dependency, we must access its
	// store by string.
	// The solution here is to split WP specific blocks from generic blocks.
	// eslint-disable-next-line @wordpress/data-no-store-string-literals
	const { getCurrentPostId, getCurrentPostType, getCurrentTemplateId } =
	select( 'core/editor' );

Would it help if I add a comment referencing this?

[ryanwelcher]

I would add the reference, yes. That way there is no confusion for reviewers or other engineers who reference this code. Thanks for the explanation!

[ryanwelcher]

Once the comment has been added I mentioned above, I'm happy with the code.

However, I'd like to get a second opinion from @t-hamano or @Mamaduka just to be sure as I am a little out of practice with the code here and don't want to miss anything.

[t-hamano]

Thanks for the PR! I left some minor feedback, but I think the overall approach is correct.

I also understand that for this block to work outside of a query context, we have to hard-code the editor store name.

[t-hamano]

LGTM!

Note that failing tests aren't related to this PR. They're a temporary problem related to the .org server. See: https://wordpress.slack.com/archives/C02QB2JS7/p1755184038359589

[Drivingralle]

Can we add support for paragaph-tag for the block?

[t-hamano]

@Drivingralle I think it's possible. Please feel free to submit an issue.