Update go examples so that errors are not ignored when parsing hex

[DaughterOfMars]

We changed the go examples to ignore these errors because it is simpler, but this means users copying these examples will get bad errors if they change the hex. We should add helper methods for parsing which will catch and print these errors as in

iota-rust-sdk/bindings/go/examples/prepare_transfer_objects/main.go

Line 12 in 8cef843

func objIdFromHex(hex string) *sdk.ObjectId {

[thibault-martinez]

Closed by #344