chore: Translate pressbooks-multi-institution.pot in es

98% of minimum 25% translated source file: 'pressbooks-multi-institution.pot'
on 'es'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

languages/pressbooks-multi-institution-es_ES.po

@@ -375,7 +375,7 @@ msgstr ""
 
 #: resources/views/partials/errors/duplicate-name.blade.php:2
 msgid "An institution with the name %s already exists."
-msgstr ""
+msgstr "Ya existe una institución con el nombre %s."
 
 #: resources/views/partials/errors/duplicate-name.blade.php:4
 msgid "Please use a different name."