compat: ignore error on checking db vendor (fixes #29926)

compat can be loaded before initialization of db in tests, we must
ignore errors at such a time.

src/authentic2/compat.py

@@ -4,6 +4,8 @@ import inspect
 import django
 from django.conf import settings
 from django.db import connection
+from django.db.utils import OperationalError
+from django.core.exceptions import ImproperlyConfigured
 
 from django.contrib.auth.tokens import PasswordResetTokenGenerator
 
@@ -25,9 +27,11 @@ default_token_generator = PasswordResetTokenGenerator()
 
 
 def has_postgresql_support():
-    if not settings.DATABASES['default'].get('NAME'):
+    try:
+        return connection.vendor == 'postgresql' and connection.pg_version > 90400
+    except (ImproperlyConfigured, OperationalError):
+        # database is not initialized, be conservative
         return False
-    return connection.vendor == 'postgresql' and connection.pg_version > 90400
 
 
 def use_django_native_field():