Function nonce_aggregator

async fn nonce_aggregator(
    nonce_streams: Vec<impl Stream<Item = Result<PublicNonce, BridgeError>> + Unpin + Send + 'static>,
    sighash_stream: impl Stream<Item = Result<(TapSighash, SignatureInfo), BridgeError>> + Unpin + Send + 'static,
    agg_nonce_sender: Sender<(AggNonceQueueItem, Vec<PublicNonce>)>,
    needed_nofn_sigs: usize,
    verifiers_ids: Vec<VerifierId>,
) -> Result<((AggregatedNonce, Vec<PublicNonce>), (AggregatedNonce, Vec<PublicNonce>)), BridgeError>

For each expected sighash, we collect a batch of public nonces from all verifiers. We aggregate and send aggregated nonce and all public nonces (needed for partial signature verification) to the agg_nonce_sender. Then repeat for the next sighash.