Media: Add "webp" extension to wp.media.controller.Library `isImageAttachment`.

Add "webp" extension to a media extension check, fixing an issue where the last used media
link type was not used for WebP images.

Props almendron, desrosj, kallookoo.
Fixes #53917.


Built from https://develop.svn.wordpress.org/trunk@52073


git-svn-id: http://core.svn.wordpress.org/trunk@51665 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-views.js

@@ -3451,7 +3451,7 @@ Library = wp.media.controller.State.extend(/** @lends wp.media.controller.Librar
 	isImageAttachment: function( attachment ) {
 		// If uploading, we know the filename but not the mime type.
 		if ( attachment.get('uploading') ) {
-			return /\.(jpe?g|png|gif)$/i.test( attachment.get('filename') );
+			return /\.(jpe?g|png|gif|webp)$/i.test( attachment.get('filename') );
 		}
 
 		return attachment.get('type') === 'image';

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52072';
+$wp_version = '5.9-alpha-52073';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.