qt: Update SetHexDeprecated to FromHex

Replace `uint256::SetHexDeprecated()` calls with `Txid::FromHex()`
in four locations:
- TransactionTableModel::updateTransaction
- TransactionView::contextualMenu
- TransactionView::abandonTx
- TransactionView::bumpFee

The input strings are generally expected to be valid hex strings
from `GetHex()`. However, due to the potentially unpredictable return
value of `.data(TransactionTableModel::TxHashRole)`, check the
`Txid::FromHex` result in `contextualMenu` and return early if the
transaction hash is invalid. The other two functions, `abandonTx`
and `bumpFee` will only be called if the context menu is enabled.

src/qt/transactiontablemodel.cpp

@@ -276,8 +276,7 @@ void TransactionTableModel::updateAmountColumnTitle()
 
 void TransactionTableModel::updateTransaction(const QString &hash, int status, bool showTransaction)
 {
-    uint256 updated;
+    Txid updated = Txid::FromHex(hash.toStdString()).value();
-    updated.SetHexDeprecated(hash.toStdString());
 
     priv->updateWallet(walletModel->wallet(), updated, status, showTransaction);
 }

src/qt/transactionview.cpp

@@ -394,9 +394,13 @@ void TransactionView::contextualMenu(const QPoint &point)
     if (selection.empty())
         return;
 
-    // check if transaction can be abandoned, disable context menu action in case it doesn't
+    // If the hash from the TxHashRole (QVariant / QString) is invalid, exit
-    uint256 hash;
+    QString hashQStr = selection.at(0).data(TransactionTableModel::TxHashRole).toString();
-    hash.SetHexDeprecated(selection.at(0).data(TransactionTableModel::TxHashRole).toString().toStdString());
+    std::optional<Txid> maybeHash = Txid::FromHex(hashQStr.toStdString());
+    if (!maybeHash)
+        return;
+
+    Txid hash = *maybeHash;
     abandonAction->setEnabled(model->wallet().transactionCanBeAbandoned(hash));
     bumpFeeAction->setEnabled(model->wallet().transactionCanBeBumped(hash));
     copyAddressAction->setEnabled(GUIUtil::hasEntryData(transactionView, 0, TransactionTableModel::AddressRole));
@@ -414,9 +418,8 @@ void TransactionView::abandonTx()
     QModelIndexList selection = transactionView->selectionModel()->selectedRows(0);
 
     // get the hash from the TxHashRole (QVariant / QString)
-    uint256 hash;
     QString hashQStr = selection.at(0).data(TransactionTableModel::TxHashRole).toString();
-    hash.SetHexDeprecated(hashQStr.toStdString());
+    Txid hash = Txid::FromHex(hashQStr.toStdString()).value();
 
     // Abandon the wallet transaction over the walletModel
     model->wallet().abandonTransaction(hash);
@@ -429,9 +432,8 @@ void TransactionView::bumpFee([[maybe_unused]] bool checked)
     QModelIndexList selection = transactionView->selectionModel()->selectedRows(0);
 
     // get the hash from the TxHashRole (QVariant / QString)
-    uint256 hash;
     QString hashQStr = selection.at(0).data(TransactionTableModel::TxHashRole).toString();
-    hash.SetHexDeprecated(hashQStr.toStdString());
+    Txid hash = Txid::FromHex(hashQStr.toStdString()).value();
 
     // Bump tx fee over the walletModel
     uint256 newHash;