ci: Complain about untranslated ui files

.gitlab-ci.yml

@@ -70,11 +70,11 @@ check-po:
     - apt-get -y update
     - apt-get -y install intltool
   script:
-    # barf on untranslated C files. Seems intltool
+    # barf on untranslated C or UI files. Seems intltool
     # can't be told to exit with non-zero exit status
     # in this case
     - cd po/
-    - intltool-update -m 2>&1 | grep -qs '/.*\.c' && { intltool-update -m; exit 1; } || exit 0
+    - intltool-update -m 2>&1 | grep -qs '/.*\.\(c|ui\)' && { intltool-update -m; exit 1; } || exit 0
 
 validate-metadata-pedantic:
   stage: test