fix: default in_app to false

Author: daibhin

posthog/exception_utils.py

@@ -733,6 +733,7 @@ def set_in_app_in_frames(frames, in_app_exclude, in_app_include, project_root=No
         # if frame has no abs_path, skip further checks
         abs_path = frame.get("abs_path")
         if abs_path is None:
+            frame["in_app"] = False
             continue
 
         if _is_external_source(abs_path):
@@ -743,6 +744,8 @@ def set_in_app_in_frames(frames, in_app_exclude, in_app_include, project_root=No
             frame["in_app"] = True
             continue
 
+        frame["in_app"] = False
+
     return frames