Fixed #33888 -- Fixed get_select2_language() crash with no language activated.

Regression in 3079133c73.

django/contrib/admin/widgets.py

@@ -456,7 +456,7 @@ SELECT2_TRANSLATIONS.update({"zh-hans": "zh-CN", "zh-hant": "zh-TW"})
 def get_select2_language():
     lang_code = get_language()
     supported_code = SELECT2_TRANSLATIONS.get(lang_code)
-    if supported_code is None:
+    if supported_code is None and lang_code is not None:
         # If 'zh-hant-tw' is not supported, try subsequent language codes i.e.
         # 'zh-hant' and 'zh'.
         i = None

docs/releases/4.1.1.txt

@@ -11,3 +11,6 @@ Bugfixes
 
 * Reallowed, following a regression in Django 4.1, using ``GeoIP2()`` when GEOS
   is not installed (:ticket:`33886`).
+
+* Fixed a regression in Django 4.1 that caused a crash of admin's autocomplete
+  widgets when translations are deactivated (:ticket:`33888`).

tests/admin_widgets/test_autocomplete_widget.py

@@ -179,6 +179,7 @@ class AutocompleteMixinTests(TestCase):
             ("sr-cyrl", "sr-Cyrl"),
             ("zh-hans", "zh-CN"),
             ("zh-hant", "zh-TW"),
+            (None, None),
         )
         for lang, select_lang in languages:
             with self.subTest(lang=lang):