Improve `ArchethicWalletClient` typing

### Is your feature request related to a problem?

_No response_

### Describe the solution you'd like

RPC method callbacks are not rigorously typed.

For example, `onAccountUpdate(accountName: string, listener: Function): PromiseLike | undefined` should specify `listener` parameter type.

### Additional context

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### Epic

_No response_

Start at the ArchethicWalletClient entry point and inspect the RPC method callback declarations, beginning with onAccountUpdate. Identify the parameter type expected by each listener instead of the generic Function type, then verify that the client’s TypeScript type checks pass.

Written by the indexing model from the issue text.