rusk-wallet: Discarded TXs are not handled properly

[HDauven]

Describe the bug
When submitting a transaction with a gas limit lower than the required minimum to execute it, the transaction is discarded from the mempool. However, the wallet continuous to wait until it is included in a block.

To Reproduce

1. Modify the MIN_LIMIT to 1 LUX and recompile
2. Create a Moonlight transaction with the limit set to 1
3. The wallet will keep asking the chain for block inclusion for the given transaction hash

Expected behaviour
If the transaction is discarded from the mempool, the wallet should catch the event for the given transaction hash and inform the user their transaction was discarded with an appropriate message that their transaction was discarded due to an insufficient gas limit.

Logs/Screenshot
This status keeps repeating: