Bug/Feature: insufficient funds

[eino-makitalo]

Current dev version at least.
Wayt to reproduce bug:
`

1. create singlekeywallet
2. make exportX( "1000000000", "C",)
   ... you will get "Insufficient Funds error"

How I fixed it

async exportX(amountAvax: string, destination:ExportChainsX): Promise<string> {
    // const fee: BN = xChain.getDefaultTxFee();
    const amount:BN = new BN(amountAvax);
    // FIX make SingleWallet to update it's uxtos
    const uxtos = await this.swallet.updateUtxosX()
    console.log("destination fro X to ", destination2);//, uxtos);
    return this.swallet.exportXChain(amount, destination2);
  }

I think there should be way to refresh Wallet state after constructing it / I understand the need separate routines which makes network calls and which are not

[eino-makitalo]

Same with exportP but not with exportC