Walletwasabi: Add popup notification if dust coin is received

[MaxHillebrand]

Problem

If a user receives a coin that is below the dust threshold, it is not shown in the GUI at all, especially not in the coinlist where the user would expect it. This makes sense if it is a forced address reuse attack or uneconomical to spend.

However, many users report confusion that they were testing Wasabi with a small value transaction, and were expecting incoming coins, but they were not displayed in the GUI.

Solution

The dust threshold makes sense, and should not be removed. However, add a new popup notification that a coin below the dust threshold was received. This message will disappear after 7 seconds, so it will not break the logic of the dust threshold, but it will notify the user that something is happening.

I'm not sure if this should be included in v1.1.10, it is a new feature after all, but part of the larger feature of proper notifications. So I say that if @danwalmsley finds a quick and non-controversial implementation, then we add it.

[MaxHillebrand]

An open question is the current Received notification includes dust coins already.
But imho regardless, there should be a separate notification that the received coin is below the dust threshold.

[yahiheb]

Users can receive the dust coin while their Wasabi is not open, therefor having a constant visual aid on the status bar maybe helpful.
An icon that indicates there are coins under the dust threshold, and maybe when hovering over it can display the number of utxos under the dust threshold.

[nopara73]

Implementation details: in the Global there's an event subscription that can be used. However it needs backend change, too, because we only have a lazy dust coin list (ReceivedDustCoins). There should be a NewlyReceivedDustCoins and NewlyConfirmedDustCoins collections too before we talk about the notifications part. It's somewhat risky, IMO either @lontivero or me should do it, or if someone else does it then write a lot of tests.

[lontivero]

The idea behind hiding the dust was to prevent the silly 'dust attacks' and that's why we decided to hide all utxo with value under a user-configurable threshold. However, if I receive a 'dust' utxo from myself then that is clearly not an attack and the utxo should be listed I think. This would avoid confusion among those that expect to receive a small change amount and that wasabi is currently hiding from them.

[nopara73]

https://github.com/zkSNACKs/WalletWasabi/pull/3235#issuecomment-599190281