Link User's Identity/Wallet with Embedded Wallet on MRU

[aashutoshrathi]

Description

Right now we are leveraging Privy to create embedded wallets for all users who sign in using their non-custodial wallet as identity. This enables high-frequency signing-on actions, without pop-ups. But this also restricts user's actual addresses from being in the state.

There are multiple things we can do to solve this:

• We authenticate each request by Privy using a standard JWT token, to extract their identity wallet address from the request. (this sets a off-chain dependency in Privy and Micro-rollup operator)
• We put this mapping of identity to embedded wallet also in the state and resolve it in transitions whenever required (this requires more thought on how to do that without creating a trust assumption in sign-up request)