Block Hooks API: Update Template Part block for first and last child hooked blocks

[tjcafferkey]

Trac ticket: https://core.trac.wordpress.org/ticket/60854

What?

This is a proof of concept exploring various ways to allow insertion of first_child and last_child insertions of hooked blocks into template parts. You can find another approach here WordPress/wordpress-develop#6867

Why?

Currently inserting hooked blocks as first_child and last_child is not possible

How?

Testing Instructions

Testing Instructions for Keyboard

function register_logout_block_as_hooked_block( $hooked_blocks, $position, $anchor_block, $context ) {
	if ( 'core/template-part' === $anchor_block && 'first_child' === $position ) {
		$hooked_blocks[] = 'core/loginout';
	}

	return $hooked_blocks;
}

add_filter( 'hooked_block_types', 'register_logout_block_as_hooked_block', 10, 4 );

Screenshots or screencast

[github-actions]

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[tjcafferkey]

Fixed in WordPress/wordpress-develop#6867