fix(nano): allow create token and withdraw on same tx

[msbrogli]

Motivation

There's a bug in the token index, where an assertion fails when we try to withdraw a nonexistent token. This PR solves this problem by adding support to unknown tokens to the TokenIndex. So all transactions keep being added to the index when they are added to the mempool. If a token does not exist, an unknown token is kept in the index to keep track of the supply and authorities. When the token is created, its information is added to the index too. If the token is never created, this unknown token entry will remain orphan in the index.

Root cause analysis

1. What's happening?

When adding a nano tx with a withdrawal action and an output of an unknown token is failing, it fails an assert in the token index, therefore causing the full node to crash.

2. Why?

Because the nano tx passes all verifications, leading to an update in the token index as the nano tx is added to the mempool. However, this index update assumes that the token already exists.

This assumption held true before we allowed contracts to dynamically create tokens. But now, it might happen that tokens do not exist when transactions reach mempool. It is actually impossible to know beforehand whether a token will exist or not after the execution.

3. Why?

The nano tx passes all verifications because we check that sum(txin) + sum(withdrawals) == sum(txout) + sum(deposits) which is true because the withdrawal of the unknown token balances out the output.

Acceptance Criteria

• Add a test demonstrating the bug.
• Refactor: Change _InfoDict type from a typed dict to a dataclass.
• Add support to unknown tokens to RocksDBTokenIndex.
• Skip unknown tokens on get_token_info() and iter_all_tokens().
• Add support for TKN.token_id to the DAG Builder to skip token creation.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[github-actions]

Bencher Report

Branch	fix/create-withdraw-same-tx
Testbed	ubuntu-22.04

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Benchmark	Latency	minutes (m)
sync-v2 (up to 20000 blocks)	📈 view plot ⚠️ NO THRESHOLD	1.95 m

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