chore: Translate transifex_input.json in es_ES

99% of minimum 50% translated source file: 'transifex_input.json'
on 'es_ES'.

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

translations/frontend-app-course-authoring/src/i18n/messages/es_ES.json

@@ -32,6 +32,8 @@
   "course-authoring.content-tags-drawer.tags-dropdown-selector.no-tags-found": "No se encontraron etiquetas con el término de búsqueda " {searchTerm} "",
   "course-authoring.content-tags-drawer.tags-dropdown-selector.selectable-box.aria.label": "{tag} casilla de verificación",
   "course-authoring.content-tags-drawer.content-tags-collapsible.selectable-box.selection.aria.label": "selección etiquetas de taxonomía",
+  "course-authoring.content-tags-drawer.button.manage": "Administrar etiquetas",
+  "course-authoring.course-unit.sidebar.tags.title": "Unit Tags",
   "course-authoring.content-tags-drawer.content-tags-collapsible.custom-menu.placeholder-text": "Añadir una etiqueta",
   "course-authoring.content-tags-drawer.content-tags-collapsible.custom-menu.save-staged-tags": "Agregar etiquetas",
   "course-authoring.content-tags-drawer.content-tags-collapsible.custom-menu.cancel-staged-tags": "Cancelar",