feat(i18n): add Tunisian Arabic (ar-TN) translation (#29306)

Signed-off-by: yyh <yuanyouhuilyz@gmail.com>
Co-authored-by: yyh <yuanyouhuilyz@gmail.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/constants/languages.py

@@ -20,6 +20,7 @@ language_timezone_mapping = {
     "sl-SI": "Europe/Ljubljana",
     "th-TH": "Asia/Bangkok",
     "id-ID": "Asia/Jakarta",
+    "ar-TN": "Africa/Tunis",
 }
 
 languages = list(language_timezone_mapping.keys())