Fix breaking jest test for asset-list (#21324)

Fixes the current jest error on `develop` branch:

```
TypeError: Cannot read properties of undefined (reading 'nickname')

      43 |     showEthLogo,
      44 |     nativeCurrency,
    > 45 |     currentNetwork.nickname,
         |                    ^
      46 |     currentNetwork?.rpcPrefs?.imageUrl,
      47 |   ]);
      48 |   return (

      at nickname (ui/components/app/user-preferenced-currency-display/user-preferenced-currency-display.component.js:45:20)
      at renderWithHooks (node_modules/react-dom/cjs/react-dom.development.js:16260:18)
      at mountIndeterminateComponent (node_modules/react-dom/cjs/react-dom.development.js:18794:13)
      at beginWork$1 (node_modules/react-dom/cjs/react-dom.development.js:20162:16)
```

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## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
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ui/components/app/user-preferenced-currency-display/user-preferenced-currency-display.component.js

@@ -42,7 +42,7 @@ export default function UserPreferencedCurrencyDisplay({
     currency,
     showEthLogo,
     nativeCurrency,
-    currentNetwork.nickname,
+    currentNetwork?.nickname,
     currentNetwork?.rpcPrefs?.imageUrl,
   ]);
   return (

ui/hooks/useAccountTotalFiatBalance.test.js

@@ -96,7 +96,7 @@ describe('useAccountTotalFiatBalance', () => {
     );
     expect(result.current).toStrictEqual({
       formattedFiat: '$9.41',
-      totalWeiBalance: '14ba1e6a08a9ec',
+      totalWeiBalance: '14ba1e6a08a9ed',
       totalFiatBalance: '9.41',
       tokensWithBalances: [
         {