Token transfer fails when no memo

[plafer]

From @yito88:

Transfers between Namada chains or from Namada to Gaia with the ibc-rs work well.
Receiving the packet failed because the packet data couldn't be decoded in my local test. The ack had the following error:

{"error":"failed to deserialize packet data"}

The packet data from Gaia didn't have the "memo" field as below.

{"amount":"100","denom":"samoleans","receiver":"atest1d9khqw36xgeyxwz9geprxseegv6yvwp5xsmygs35xscng3fjxumnssenxvurwv2y89qnxs2p8yj8f3","sender":"cosmos19hav62pmlg53fxd3lryc768kwhde7l2ffc8rnf"}

Hermes command to transfer from Gaia:

hermes --config config_for_namada.toml tx ft-transfer --dst-chain namada-test.170f420af02f48796c --src-chain gaia-1 --src-port transfer --src-channel channel-0 --amount 100 --receiver atest1d9khqw36xgeyxwz9geprxseegv6yvwp5xsmygs35xscng3fjxumnssenxvurwv2y89qnxs2p8yj8f3 --denom samoleans --timeout-height-offset 1000

When I tried to transfer a token with --memo test from Gaia, receiving the packet worked well.

hermes --config config_for_namada.toml tx ft-transfer --dst-chain namada-test.170f420af02f48796c --src-chain gaia-1 --src-port transfer --src-channel channel-0 --amount 100 --receiver atest1d9khqw36xgeyxwz9geprxseegv6yvwp5xsmygs35xscng3fjxumnssenxvurwv2y89qnxs2p8yj8f3 --denom samoleans --timeout-height-offset 1000 --memo test

I'm using,
ibc-rs: v0.41.0
Hermes: forked based on v1.6.0
Gaia: v9.0.3