Explain how client updates account data by asserting on balance

Reference: https://github.com/0xMiden/miden-client/issues/1261#issuecomment-3258703959

Basically, a user was confused because of the balance of `account` being outdated. What we could do in the tutorial is specify that as a user you can retrieve the account again and see what the updated balance is.

Find the tutorial file(s) that cover account data updates, likely in the tutorials repository. Look for where account balance retrieval is explained. Add a step or note instructing users to retrieve the account again to see the updated balance after a transaction. Verify by running any existing tutorial examples to ensure the flow is clear.

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