fix: graph for non-pythonic container output's names

Loading container component from component.yaml creates both
pythonic and original output names. Graph component iterated over
all outputs, using pythonic-to-output conversion on all. If some
of the names are not identical to their pythonic versions, they
rised KeyError on the lookup table.

This commit fixes this problem by using default value for the lookup.

sdk/python/kfp/components/_components.py

@@ -537,7 +537,12 @@ def resolve_argument(argument):
 
         task_obj = task_factory(**pythonic_task_arguments)
         task_outputs_with_pythonic_names = task_obj.outputs
-        task_outputs_with_original_names = {pythonic_output_name_to_original[pythonic_output_name]: output_value for pythonic_output_name, output_value in task_outputs_with_pythonic_names.items()}
+        task_outputs_with_original_names = {
+            # component_bridge generates outputs under both pythonic and original name,
+            # so half of them are absent from pythonic_output_name_to_original
+            pythonic_output_name_to_original.get(pythonic_output_name, pythonic_output_name): output_value
+            for pythonic_output_name, output_value in task_outputs_with_pythonic_names.items()
+        }
         outputs_of_tasks[task_id] = task_outputs_with_original_names
 
     resolved_graph_outputs = OrderedDict([(output_name, resolve_argument(argument)) for output_name, argument in graph.output_values.items()])