[MNY-232] SDK: Fix ExecutingTxScreen missing back button in TransactionWidget (#8193)

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## PR-Codex overview
This PR focuses on enhancing the transaction handling in the `TransactionWidget` and `TransactionModal` components by ensuring that the `onBack` function is defined and properly utilized.

### Detailed summary
- In `TransactionWidget.tsx`, added `onBack` function to `ExecutingTxScreen` that sets the screen to `init-ui`.
- In `TransactionModal.tsx`, modified `onBack` to set the screen to `"deposit"`.
- In `ExecutingScreen.tsx`, changed `onBack` from optional to required.

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Author: MananTank

packages/thirdweb/src/react/web/ui/Bridge/TransactionWidget.tsx

@@ -770,6 +770,9 @@ function TransactionWidgetContent(
   if (screen.id === "execute-tx") {
     return (
       <ExecutingTxScreen
+        onBack={() => {
+          setScreen({ id: "init-ui" });
+        }}
         closeModal={() => {
           setScreen({ id: "init-ui" });
         }}

packages/thirdweb/src/react/web/ui/TransactionButton/ExecutingScreen.tsx

@@ -20,7 +20,7 @@ export function ExecutingTxScreen(props: {
   tx: PreparedTransaction;
   closeModal: () => void;
   onTxSent: (data: WaitForReceiptOptions) => void;
-  onBack?: () => void;
+  onBack: (() => void) | undefined;
   windowAdapter: WindowAdapter;
 }) {
   const sendTxCore = useSendTransaction({

packages/thirdweb/src/react/web/ui/TransactionButton/TransactionModal.tsx

@@ -133,6 +133,9 @@ function DepositAndExecuteTx(props: ModalProps) {
   if (screen === "execute-tx") {
     return (
       <ExecutingTxScreen
+        onBack={() => {
+          setScreen("deposit");
+        }}
         closeModal={props.onClose}
         onTxSent={props.onTxSent}
         tx={props.tx}