Tests

Enable Python workflow with `BytePairTokenizer` and `StartEndPacker` #9941

Job	Run time
Check the code format	1m 59s
Test the code (jax, keras-stable)	1h 3m 59s
Test the code (jax, keras-3.13)	56m 17s
Test the code (jax, keras-nightly)	1h 4m 44s
Test the code (torch, keras-stable)	21m 10s
Test the code (openvino, keras-nightly)	3m 59s
Test the code (tensorflow, keras-stable)	41m 36s
	4h 13m 44s

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