Simple & shielded transfers are always transfers with memo

[jens-concordium]

Bug Description Even though no memo has been added to a simple or shielded transaction, the transaction is always of the type that contains a memo. The memo field is just empty.

When a memo is not entered during the "transaction setup" in the wallet, the wallet should just use the old simple and shielded transactions without memos, as the new type is slightly more expensive.

This bug is related to https://github.com/Concordium/concordium-reference-wallet-android/issues/22

Steps to Reproduce

• Start making a simple or shielded transaction.
• Enter everything, except a memo.
• Submit transaction, and wait for it to finalize.
• Find the block in the block explorer by adding "/" to the end of this link: https://dashboard.testnet.concordium.com/chain
• Notice how the transaction is actually a transaction with a memo, but with an empty memo field.

Expected Result

• When no memo is added, the wallet should use the old types of transactions.

Actual Result

• When no memo is added the wallet still uses the type of transaction that contains memos.

Versions

• Software Version: 1.0.14
• OS: Android

[jens-concordium]

Verified in 1.0.15.