[Request]: Check if TransactionSigner::iotaPublicKeyBytes() is still needed

### Feature description

In the past we were facing problems with converting a public key from TS to Rust and vice-versa.

For this reason the [TransactionSigner](https://github.com/iotaledger/product-core/blob/main/bindings/wasm/iota_interaction_ts/src/bindings/wasm_transaction_signer.rs) interface offers two functions, `iotaPublicKeyBytes: () => Promise` and `publicKey: () => Promise` to access the public key.

We might have fixed the issue that made unreliable the conversion of a public key from TS to Rust and vice-versa.

This should be checked. If conversion is no more unreliable we should remove the function `iotaPublicKeyBytes()` from the `TransactionSigner` interface.

### Motivation

Avoid unneeded code

### Requirements

-

### Open questions

_No response_

### Are you planning to do it yourself in a pull request?

Yes