ui: wallet balance should always use standard (and correct) units

[norwnd]

I've noticed on wallets page my token-wallets show weird units:

• for some reason it shows USD denomination (while it should be USDC and USDT accordingly)
• showing it in milli/micro units is a bit confusing, this way if you don't specifically look at the unit you might compare/assess balances across wallets (eg. USDC and USDT) incorrectly; and just changing units by itself based on the balance value doesn't make much sense from UI/UX perspective

it seems to manifest when balance drops very low (close to 0, essentially dust values) and maybe only for ERC20 tokens, but I'm not 100% sure about that part

seems like only sidebar balances are affected