fix(permissions): raise error if user is missing in context

Silently ignoring this makes it easy to miss user in some inclusion
template tags and the permission check then silently returns false.

weblate/auth/templatetags/permissions.py

@@ -11,6 +11,8 @@
 def perm(context, permission, obj=None):
     try:
         user = context["user"]
-    except KeyError:
-        return False
+    except KeyError as error:
+        raise ValueError(
+            "Missing user in context, could not perform permission check"
+        ) from error
     return user.has_perm(permission, obj)