Fix/daef 468 Frontend AtoA transaction handling

[nikolaglumac]

This PR introduces improved error messages for transaction-fees-calculation endpoint.

TODO

• Inject missing Japanese translation

"api.errors.AllFundsAlreadyAtReceiverAddressError": "All your funds are already at the address you are trying send money to.",

[DominikGuzei]

Reviewing this now …

[DominikGuzei]

@nikolaglumac how can i reproduce this? I sent two transactions from "Genesis wallet" to two different addresses of itself (taken from receive screen) and it worked without any errors..

[DominikGuzei]

I ran backend on cardano-sl-0.6--0.6.2-candidate (commit: 9f5b591e7365c9723cca02ee8fbb284957b0fb42) and started it with ./scripts/launch/connect-to-cluster/testnet-staging-0.6.sh

[nikolaglumac]

@DominikGuzei here are the steps to reproduce both errors:

1. A -> A error aka. All your funds are already at the address you are trying send money to.

• import new Genesis wallet which has never been used before (aka. transaction history is empty and wallet has only single address)
• try to send any amount to the single address of imported wallet

2. A -> B error for sending too much money aka. Not enough Ada for fees.

• use the same imported wallet from first step and try to send amount larger than the wallet's balance to some other wallet (eg. create/import/restore another wallet and use it's address as receiver)

I also used cardano-sl-0.6--0.6.2-candidate branch BUT I use ./scripts/launch/connect-to-cluster/testnet-0.6.sh script to launch it - but I don't think it should matter...

[DominikGuzei]

@nikolaglumac i will push the missing translation now

[DominikGuzei]

I could reproduce both error cases and pushed the missing japanese translation 👍 ready to merge

[DominikGuzei]

Closing this PR in favor of new target against release/0.8.2