i18n: add missing Spanish translation (#13232)

src/locale/lang/es.js

@@ -81,7 +81,7 @@ export default {
       error: 'Entrada inválida'
     },
     upload: {
-      deleteTip: 'press delete to remove', // to be translated
+      deleteTip: 'Pulse Eliminar para retirar',
       delete: 'Eliminar',
       preview: 'Vista Previa',
       continue: 'Continuar'