Improve Bitcoin deposit transaction detection

[r-czajkowski]

We could improve it for the Ledger Live integration, as we should be able to get a Bitcoin transaction hash while broadcasting it in the staking flow.

Originally posted by @nkuba in #106 (comment)

[r-czajkowski]

Example solution:

Ref: #106 (comment)

  async stake(fundingTxHash?: Hex): Promise<Hex> {
    if (!this.#signedMessage) {
      throw new Error("Sign message first")
    }

    const utxos = await this.#tbtcDeposit.detectFunding()

    if (utxos.length === 0) {
      throw new Error("Deposit not found yet")
    }

    // NEW CODE HERE: Find utxo by transaction hash 
    let utxo: BitcoinUtxo
    if (fundingTxHash) {
      const foundUtxo = utxos.find(({ transactionHash }) =>
        transactionHash.equals(fundingTxHash),
      )

      if (!foundUtxo) throw new Error("Deposit not found yet")

      utxo = foundUtxo
    }
  
    ;[utxo] = utxos

    const { transactionHash, outputIndex } = utxo

    const depositFundingTx = extractBitcoinRawTxVectors(
      await this.#bitcoinClient.getRawTransaction(transactionHash),
    )

    const { depositor: _, ...restDepositReceipt } =
      this.#tbtcDeposit.getReceipt()

    const revealDepositInfo = {
      fundingOutputIndex: outputIndex,
      ...restDepositReceipt,
    }

    // TODO: change it to the deposit details submission to the relayer bot.
    return this.#contracts.tbtcDepositor.initializeStake(
      depositFundingTx,
      revealDepositInfo,
      this.#staker,
      this.#referral,
    )
  }