Localize Text wraps empty block attribute values in a translation call #879

Description

When Localize Text exports a block attribute whose value is an empty string, it wraps it in a translation call anyway. For example, an Excerpt block with an empty "Read more" text:

<!-- wp:post-excerpt {"moreText":""} /-->

is written to the theme as:

<!-- wp:post-excerpt {"moreText":"<?php esc_attr_e('', 'my-theme');?>"} /-->

That adds an empty string to the theme's translatable strings, and WordPress Coding Standards flag it (WordPress.WP.I18n.NoEmptyStrings). We found three of these in a theme exported with Create Block Theme (the Excerpt blocks in its index, archive and search patterns).

Cause

escape_block_attribute() has no empty-string check:
https://github.com/WordPress/create-block-theme/blob/trunk/includes/create-theme/theme-locale.php#L26

The other two escape functions in the same file already return an empty string unchanged (escape_text_content() and escape_attribute(), "Check if string is empty.").

Steps to reproduce

With Create Block Theme 2.10.1 (the same code is on trunk):

echo CBT_Theme_Locale::escape_block_attribute_strings( '<!-- wp:post-excerpt {"moreText":""} /-->' );
// <!-- wp:post-excerpt {"moreText":"<?php esc_attr_e('', 'my-theme');?>"} /-->

Expected behavior

Empty attribute values are left as they are, e.g. "moreText":"". A possible fix is to skip empty strings in escape_block_attribute_strings() (or in escape_block_attribute()), matching the other two functions.

Drafted with AI assistance, reproduced and verified by me.