Media: Prevent uploading and show an error message when the server doesn't support editing of WebP images, take II. Add new, better error message for it.

Props antpb, joedolson, iandunn, azaozz.
Fixes #53475.

git-svn-id: https://develop.svn.wordpress.org/trunk@51227 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/script-loader.php

@@ -875,6 +875,7 @@ function wp_default_scripts( $scripts ) {
 		/* translators: %s: File name. */
 		'error_uploading'           => __( '“%s” has failed to upload.' ),
 		'unsupported_image'         => __( 'This image cannot be displayed in a web browser. For best results convert it to JPEG before uploading.' ),
+		'noneditable_image'         => __( 'This image cannot be processed by the web server. Convert it to JPEG or PNG before uploading.' ),
 		'file_url_copied'           => __( 'The file URL has been copied to your clipboard' ),
 	);