[Bug]: Balances displayed before all values have been determined on wallet restore

[catch-21]

Raising off the back of https://github.com/synonymdev/bitkit/issues/1841.

On wallet restore, the main screen is displayed before all balances have been determined. This can mean showing 0 for some balance (or flicking between some value and 0) for a short while before displaying the correct value.

We could either wait at the rocket or give some visual indication on the main screen to minimise confusion, such as some loading icon instead of 0.

Couple of examples of how it behaves atm on restore for two of my wallets:

https://github.com/synonymdev/bitkit/assets/74595920/dbca6291-c876-4731-a9b7-63914ad4a9e3

https://github.com/synonymdev/bitkit/assets/74595920/49673845-6e68-4788-8169-e48c31e360f1