fix(multichain): fix missing async for CreateBtcAccount.onActionCompl…

…ete callback

## **Why do we need this fix?**
Why do we need this fix?

This produces a linting error, now that `account-menu-list` is a `.tsx`
file.

## **Why don't we have this error on `develop`?**

This is because we are cherry-picking specific commits for BTC fixes,
but not all! (otherwise this would introduce much more changes)

The commit that converts `account-menu-list.js` to `.tsx` was not using
`CreateBtcAccount` on `develop` since this component has been replaced
by the new "Snap account creation flow" (which is not part of the
v12.2.0).

During the merge and conflict resolution, the `CreateBtcAccount` has
been kept, and now that we are using TypeScript for this file, this new
typing error occurs.

ui/components/multichain/account-list-menu/account-list-menu.tsx

@@ -273,7 +273,7 @@ export const AccountListMenu = ({
           bitcoinSupportEnabled && actionMode === ACTION_MODES.ADD_BITCOIN ? (
             <Box paddingLeft={4} paddingRight={4} paddingBottom={4}>
               <CreateBtcAccount
-                onActionComplete={(confirmed) => {
+                onActionComplete={async (confirmed) => {
                   if (confirmed) {
                     onClose();
                   } else {