fix: filter lang map

[arzola]

Problem

• Transifex translations are not working as expected, we introduced a change https://github.com/pressbooks/pressbooks-aldine/pull/430 to try to setup automated github sync with transifex but we are dealing with some issues regarding duplicate translation resources and missing translations.

Translation files filenames

Before

languages/es_ES.mo

Now

languages/pressbooks-aldine-es_ES.mo

Solution

• Revert the translation prefix change because the old translations on this plugin are not using a prefix like pressbooks does, you can look at previous commits files doesn't contains a prefix https://github.com/pressbooks/pressbooks-aldine/commit/7e6ef6b2e8f30317783c21ab95460b26ef37bbb9

After this change

languages/es_ES.mo