[UI] Auto label transactions going to whirlpool

[RequestPrivacy]

I just noticed that transactions going out of the deposit and into the whirlpool premix account don't get automatically a label. This could lead to confusion if you're behind with proper labeling of your transactions.

It would be much more convenient if Sparrow would automatically label these transactions in the transaction tab as "whirlpool", "send to premix", or something more private/generic like "self-transfer".

Users which are extremely privacy aware could manually delete the label afterwards to erase the "hint" (should be minority and makes not too much sense as pre-, post- and badbank account tab give away that you're using whirlpool anyway).

[Transisto]

The default labeling should be enough, but I don't know why it's not working for mixes, The label seems to be set at the right places.

[craigraw]

I'm not sure I'm keen on automatic labelling, which will always be generic and thus limited in value. Also, one downside is that should a user later want to change the automatically applied transaction label, their change will not be applied to the associated TXOs/TXIs (since these will be already set).