[Claim] Use blockies for wallet avatars instead of identicon

[alfetopito]

@alfetopito Tuning in here: I'd personally stick to the 'blockies' avatar for all wallets:

• We can't detect the MetaMask setting the users has (e.g. you can enable/disable blockies in settings). So even with MM users there's a potential mismatch.
• All other external block explorers/wallet managers use Blockies (Etherscan, Zerion, Gnosis Safe, Zapper, etc.).

Originally posted by @biocom in https://github.com/gnosis/cowswap/issues/2161#issuecomment-1014599678

[anxolin]

Agree, although i also see this as low prio