numberDecoder fails to parse long numbers, even with `UseNumbers()` enabled.

[atoulme]

See open-telemetry/opentelemetry-collector-contrib#41028 for origination.

The issue seems to come from folks sending overly long numbers as struct fields. Even with UseNumbers() enabled, we get an error.

This is because https://github.com/goccy/go-json/blob/master/internal/decoder/number.go#L45 performs a check:

	if _, err := strconv.ParseFloat(*(*string)(unsafe.Pointer(&bytes)), 64); err != nil {
		return 0, errors.ErrSyntax(err.Error(), c)
	}

Why is this check present? Is it to conform to json/encoding?