fix: access correct attribute for tracebackhide check

Author: untitaker

sentry_sdk/utils.py

@@ -144,11 +144,10 @@ def get_type_module(cls):
 
 def iter_stacks(tb):
     while tb is not None:
-        f_locals = getattr(tb, "f_locals", None)
         skip = False
         for flag_name in "__traceback_hide__", "__tracebackhide__":
             try:
-                if f_locals[flag_name]:
+                if tb.tb_frame.f_locals[flag_name]:
                     skip = True
             except Exception:
                 pass