fix: Handle channels shadowing

Author: sentrivana

sentry_sdk/integrations/threading.py

@@ -57,7 +57,7 @@ def setup_once() -> None:
             import channels  # type: ignore[import-untyped]
 
             channels_version = channels.__version__
-        except ImportError:
+        except (ImportError, AttributeError):
             django_version = None
             channels_version = None