fix: auth server and sdk when not using sessions

[MexicanAce]

Description

The use of SSO accounts without sessions is currently broken for users. Here's the fixes in this PR:

1. Creating an account without sessions in the Auth Server will now properly navigate to the final confirmation screen
2. Creating an account with a session will now display Create (instead of Connect) for the confirmation button
3. Using a paymaster with Passkey Clients now works

Additional context

As part of this, I added a generic paymaster to the demo-app and updated the UI to have buttons for connecting with and without a session, also transferring 0.1 ETH with and without a paymaster.

New landing page:

Once connected:

I've also added deployment scripts to the paymaster using zksync-foundry. This feels like the best way to include contracts into front-end apps without creating an entirely new project.

Note: I am generating a forge-output.json file every time we deploy the generic paymaster, and using that in the demo-app

[github-actions]

Visit the preview URL for this PR (updated for commit 27f99b3):

https://zksync-auth-server-staging--pr45-nmv-address-issues-w-y5kawz67.web.app

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