the existing LogInWalletUser RPC now handles login exclusively. Thew new Register RPC will handle registration exclusively. Changes in this diff:
- Introduced new RPC in .proto file and renamed WalletLoginRequest -> WalletAuthRequest so we can use it for both registration and login
- Implemented the new register RPC on the identity service, and updated the existing login RPC to only handle login
- Updated grpc-web codegen to reflect the .proto changes
- Updated the native_rust_library to use the new WalletAuthRequest message name
Depends on D11062