feat(agent): return SerializationError instead of aborting (#121)

src/isolate/connections/grpc/agent.py

@@ -108,11 +108,8 @@ def execute_function(
             # TODO: technically any sort of exception could be raised here, since
             # depickling is basically involves code execution from the *user*.
             function = from_grpc(function)
-        except SerializationError:
-            yield from self.log(traceback.format_exc(), level=LogLevel.ERROR)
-            raise AbortException(
-                f"The {function_kind} function could not be deserialized."
-            )
+        except SerializationError as exc:
+            return exc, True, traceback.format_exc()
 
         if not callable(function):
             raise AbortException(