Online status for nodes using username and password broken

[slack2450]

Describe the bug
Cake wallet shows a red circle next to nodes using username and password. Disabling username and password makes this show green.

Looking through the code this section appears to be the issue:
https://github.com/cake-tech/cake_wallet/blob/main/cw_core/lib/node.dart#L196

I don't see the nonce for the session being sent, I believe that we should fetch the nonce first if using authentication and send this in the request to check if a node is online.

Here is where monerod checks for a valid nonce:
https://github.com/monero-project/monero/blob/master/contrib/epee/src/http_auth.cpp#L326

If a nonce is not provided or is stale it will return a 401 unauthorized response. This results in online checks always failing.

Platform:

• OS: iOS
• Device: iPhone 15
• Cake Wallet Version: 4.21.2