fix: add json serialization support for neo4j sdk types #455

Job	Run time
search	4s
test (lib/metadata)	9s
test (lib/wasmextractor)	13s
test (lib/manifest)	10s
test (sdk/go)	12s
test (sdk/go/examples/graphql)	18s
test (sdk/go/examples/time)	14s
test (sdk/go/examples/simple)	23s
test (sdk/go/examples/auth)	20s
test (sdk/go/examples/anthropic-functions)	15s
test (sdk/go/examples/postgresql)	12s
test (sdk/go/examples/dgraph)	12s
test (sdk/go/examples/embedding)	11s
test (sdk/go/examples/vectors)	20s
test (sdk/go/examples/collections)	13s
test (sdk/go/examples/classification)	12s
test (sdk/go/examples/neo4j)	12s
test (sdk/go/examples/textgeneration)	18s
test (sdk/go/examples/http)	18s
test (sdk/go/templates/default)	18s
test (runtime)	1m 2s
test (runtime/languages/golang/testdata)	13s
	5m 59s

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