bug(l1): peer connection broken due to failure to add transaction to mempool before sync

[fmoletta]

When we have just launched our node and try to connect to potential syncing peers we will also get transactions to add to our mempool. As our state is not synced we will often fail to validate and add these transactions to our mempool due to insufficient account funds. When this fails the error is propagated to the peer connection loop, ending it.