[Desktop] Some asset icons not present for Binance widget

[bbondy]

Description

Depending on the region, some asset icons are not available.

We should be getting the icons when the user has manually connected from this endpoint:
https://www.binance.com/exchange-api/v1/public/asset/asset/get-all-asset

Note: When this is implemented we should do a privacy review, I believe the assets will be served from cache after the first access. but a privacy review should be done.

For the disconnected view, we should only consider asset icons we have on hand so that no network calls are made by default.

Steps to Reproduce

I'm not sure how to reproduce, but I assume if you setup your account to with a different country you can see some assets without an icon

Reproduces how often:

Always or never, depending on the user.

• Can you reproduce this issue with the current release? yes
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the dev channel? yes
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? no
• Does the issue resolve itself when disabling Brave Rewards? no
• Is the issue reproducible on the latest version of Chrome? n/a