fix: Remove unused import

Author: untitaker

sentry_sdk/integrations/gnu_backtrace.py

@@ -3,7 +3,7 @@
 from sentry_sdk.hub import Hub
 from sentry_sdk.integrations import Integration
 from sentry_sdk.scope import add_global_event_processor
-from sentry_sdk.utils import walk_exception_chain, capture_internal_exceptions
+from sentry_sdk.utils import capture_internal_exceptions
 
 if False:
     from typing import Any