Upgrade scalapb-json4s for conformance #2279

Job	Run time
conformance	1m 30s
build (2_12, e2e)	3m 19s
build (2_12, test)	9m 36s
build (2_13, e2e)	4m 12s
build (2_13, test)	11m 7s
build (3, e2e)	4m 23s
build (3, test)	10m 18s
build (2_12, examples_and_formatting)	2m 54s
build (2_13, scala3_compat_test)	10m 11s
build (3, scala3_compat_test)	8m 40s
ci-passed	0s
	1h 6m 10s

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