Qt AddressList: mark address if some coins are frozen

[SomberNight]

If some coins are frozen in the wallet (but not addresses), the Addresses tab of the Qt GUI does not give any clues to the user about this. I think if there is an address which is not frozen itself but some related UTXOs are, the interface should show that somehow.

I don't know how to do it nicely though... In this PR, as before, a frozen address has a solid blue background colour; and now if there are some frozen coins, the address has a background in a different style.

related: #8035 (comment)

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I've done some benchmarking on large wallets, and this makes AddressList.refresh_all() around 2x slower.
(due to calculating the utxos for an address: wallet.adb.get_addr_utxo(address))
Regardless, I think the slowdown is acceptable.

[SomberNight]

In this PR, as before, a frozen address has a solid blue background colour; and now if there are some frozen coins, the address has a background in a different style.

Ahh, this looks really bad when using the dark style. The states are difficult to distinguish.
Actually, in the dark style, I don't particularly like any of the brush styles for the background.
I would rather not use a different colour than blue either, as blue is intuitive for frozen (or at least users already learned it).

Maybe we need a different approach; e.g. adding an icon in a new column.

[ecdsa]

what is the use case for freezing a coin without freezing the address?
how about we remove that functionality?

[SomberNight]

what is the use case for freezing a coin without freezing the address?

For example #6962 (and more generally #6960), which is also the cause of confusion in #8035.

There is also prior discussion in #4053, #5061, #5313.

[ecdsa]

my point is that this is redundant with the freeze threshold.
the cause of the confusion is that we have both manual freeze and the threshold.

[SomberNight]

Even if we removed manual utxo freezing from the gui, but kept automatic utxo freezing (for the current use case of unconfirmed dust, and potential future use cases), I think it would be still useful to give a hint to the user in the Addresses tab.

But I would like to keep manual utxo freezing, I think it's a nice power-user feature, which most users likely never interact with but it should not affect them negatively either.