po: fix LINGUAS to use whitespace separation

The po/LINGUAS file contains a list of all avilable translations.
According to the GNU gettext documentation it's is a whitespace
separated list. Our LINGUAS file used newline separated list with inline
comments. This conflicts with weblate automation.

Fixes: https://pagure.io/freeipa/issue/8159
See: https://www.gnu.org/software/gettext/manual/html_node/po_002fLINGUAS.html
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

po/LINGUAS

@@ -1,24 +1 @@
-bn_IN   # Bengali (India)
+bn_IN ca cs de en_GB es eu fr hi hu id ja kn mr nl pa pl pt pt_BR ru sk tg uk zh_CN
-ca      # Catalan
-cs      # Czech
-de      # German
-en_GB   # English (United Kingdom)
-es      # Spanish
-eu      # Basque
-fr      # French
-hi      # Hindi
-hu      # Hungarian
-id      # Indonesian
-ja      # Japanese
-kn      # Kannada
-mr      # Marathi
-nl      # Dutch
-pa      # Punjabi
-pl      # Polish
-pt      # Portuguese
-pt_BR   # Portuguese (Brazil)
-ru      # Russian
-sk      # Slovak
-tg      # Tajik
-uk      # Ukrainian
-zh_CN   # Chinese (China)