wysiwyg: set the default link protocol to https (#4291)

See https://www.tiny.cloud/docs/plugins/opensource/link/#link_default_protocol

when you don't enter a protocol, and tinyemc thinks you entered an external link, it will prompt you to add https

app/src/interfaces/wysiwyg/wysiwyg.vue

@@ -155,6 +155,7 @@ export default defineComponent({
 				file_picker_types: 'image media',
 				file_picker_callback: setImageUploadHandler,
 				urlconverter_callback: urlConverter,
+				link_default_protocol: 'https',
 				...(props.tinymceOverrides || {}),
 			};
 		});