Remove unnecessary show_in_rest conditional

Co-authored-by: Pascal Birchler <pascalb@google.com>

lib/compat/wordpress-6.5/block-bindings/post-meta.php

@@ -37,7 +37,7 @@ function gutenberg_block_bindings_post_meta_callback( $source_attrs, $block_inst
 	$meta_keys = get_registered_meta_keys( 'post', $block_instance->context['postType'] );
 	// Add fields registered for all subtypes.
 	$meta_keys = array_merge( $meta_keys, get_registered_meta_keys( 'post', '' ) );
-	if ( empty( $meta_keys[ $source_attrs['key'] ]['show_in_rest'] ) || false === $meta_keys[ $source_attrs['key'] ]['show_in_rest'] ) {
+	if ( empty( $meta_keys[ $source_attrs['key'] ]['show_in_rest'] ) ) {
 		return null;
 	}