Comments: Avoid PHP notice in `get_comment_reply_link()` for `null` comment.

If there is no global comment, or the input comment is null, return early to prevent warnings.

Fixes #41846
Props birgire, earnjam


Built from https://develop.svn.wordpress.org/trunk@46335


git-svn-id: http://core.svn.wordpress.org/trunk@46134 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/comment-template.php

@@ -1646,6 +1646,10 @@ function get_comment_reply_link( $args = array(), $comment = null, $post = null
 
 	$comment = get_comment( $comment );
 
+	if ( empty( $comment ) ) {
+		return;
+	}
+
 	if ( empty( $post ) ) {
 		$post = $comment->comment_post_ID;
 	}

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-beta1-46334';
+$wp_version = '5.3-beta1-46335';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.