Comment Template Block: Set commentId context via filter (#50279)

In the Comment Template block's render callback, instead of creating a new `WP_Block` instance with `commentId` context set, use the `render_block_context` filter to set that context and render the existing `WP_Block` instance.

This approach arguably follows our established patterns with regard to handling block context better. Notably, with the previous approach, we were only setting block context for the Comment Template block itself. In this PR, we extend it to apply to all child blocks, including ones that are dynamically inserted, e.g. via the `render_block` filter. This is relevant for Auto-inserting blocks (see #50103).

packages/block-library/src/comment-template/index.php

@@ -25,13 +25,14 @@ function block_core_comment_template_render_comments( $comments, $block ) {
 
 	$content = '';
 	foreach ( $comments as $comment ) {
-
-		$block_content = ( new WP_Block(
-			$block->parsed_block,
-			array(
-				'commentId' => $comment->comment_ID,
-			)
-		) )->render( array( 'dynamic' => false ) );
+		$comment_id           = $comment->comment_ID;
+		$filter_block_context = static function( $context ) use ( $comment_id ) {
+			$context['commentId'] = $comment_id;
+			return $context;
+		};
+		add_filter( 'render_block_context', $filter_block_context );
+		$block_content = $block->render( array( 'dynamic' => false ) );
+		remove_filter( 'render_block_context', $filter_block_context );
 
 		$children = $comment->get_children();