[prism] Python Validates Runner (test_pack_combiners) - Unknown Coder not being processed (tuple)

[lostluck]

Make test_pack_combiners in prism_runnter_test pass.

Long iteration cycle will be against

./gradlew :sdks:python:test-suites:portable:prismValidatesRunner

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Mostly means being able to "understand" or at least not fail the packed combiner approaches.