ADD: add tx hash to Loan open and repayment events #check-lint-warning

fixes: #1656 (closed)

loan_open event:

    {
      "collateral_asset": "BTC.BTC",
      "collateral_deposited": "493885",
      "collateralization_ratio": "10000",
      "debt_issued": "483710000",
      "owner": "bcrt1q3wrmhnh2qe98rjse30pl7u6jxszjjwl44ls6uw",
      "target_asset": "THOR.RUNE",
      "tx_id": "0000000000000000000000000000000000000000000000000000000000000008",
      "type": "loan_open"
    }

loan_repayment event:

{
      "collateral_asset": "BTC.BTC",
      "collateral_withdrawn": "989774",
      "debt_repaid": "4180150193",
      "owner": "bcrt1q3wrmhnh2qe98rjse30pl7u6jxszjjwl44ls6uw",
      "tx_id": "0000000000000000000000000000000000000000000000000000000000000006",
      "type": "loan_repayment"
 }