chore: drop validToken test token

[miraclx]

Resolves #76. Provided FE no longer needs this, we can proceed to remove it.

If they're still dependent on this, we can make the process a bit more dynamic, to reduce the chances of an exploit.

[itegulov]

The problem is that this breaks integration tests as we have not figured out how to imitate Firebase there. We could maybe hide these fake tokens behind a feature flag for now?

[volovyks]

This logic does not make any sense anymore. Let's delete it and jsut use PagodaFirebaseTokeVerifier in verify token.

[volovyks]

@miraclx do you have time to continue working on this PR?

[miraclx]

Stuck on this note in the sign_node /commit path: https://github.com/near/mpc-recovery/blob/21839cdc8478b9ed6a43c53328a94e24df64c53d/mpc-recovery/src/sign_node/mod.rs#L72-L74

It's unclear how to extract the access token from the payload. The structure of the payload is undocumented. In the two cases I can find;

1. Random alphanumeric
   https://github.com/near/mpc-recovery/blob/21839cdc8478b9ed6a43c53328a94e24df64c53d/integration-tests/tests/mpc/positive.rs#L29
2. Hash (so there's nothing to extract from here):
   https://github.com/near/mpc-recovery/blob/21839cdc8478b9ed6a43c53328a94e24df64c53d/mpc-recovery/src/transaction.rs#L127

I need context on how this is used in prod to define a proper resolution for this.

[itegulov]

@miraclx try rebasing on my branch from #103, I am extracting the token there

[volovyks]

Looks like this PR is not relevant anymore. @miraclx feel free to reopen if you still want to merge something.