chore: do not show staked eth balance when balance is zero on homepag…

…e or asset detail (#12332)

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## **Description**

1. What is the reason for the change?

We have decided that we should hide the staked ethereum balance if it is
0 on mobile.

3. What is the improvement/solution?

Ensure that the staked ethereum asset does not show when the balance is
zero on the homepage and on the ETH asset detail page.

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Write a short description of the changes included in this pull request,
also include relevant motivation and context. Have in mind the following
questions:
1. What is the reason for the change?
2. What is the improvement/solution?
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## **Related issues**

Fixes: https://consensyssoftware.atlassian.net/browse/STAKE-874

## **Manual testing steps**

1. On this branch 
2. If you have a zero Staked ETH balance, you should see no Staked
Ethereum asset on the homepage or on the ETH asset detail page after
clicking the ETH asset on homepage.
3. If you do have Staked ETH already, then you should see that ETH on
the homepage and on the ETH asset detail page as well. Unstake Max ETH
and wait for transaction to confirm. When you check homepage and ETH
asset detail page, there should be no Staked Ethereum listed as balance
is now 0.

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**


https://github.com/user-attachments/assets/04e475ad-f8c0-49f1-aaeb-a5a8df25e44b

<!-- [screenshots/recordings] -->

### **After**

<!-- [screenshots/recordings] -->


https://github.com/user-attachments/assets/35ea9834-ff42-4667-87d2-cc510ff91155

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

app/components/UI/Stake/components/StakingBalance/StakingBalance.tsx

@@ -166,7 +166,7 @@ const StakingBalanceContent = ({ asset }: StakingBalanceProps) => {
 
   return (
     <View>
-      {hasStakedPositions && (
+      {hasEthToUnstake && (
         <AssetElement
           asset={asset}
           mainBalance={stakedBalanceETH}

app/components/Views/Wallet/index.tsx

@@ -481,10 +481,12 @@ const Wallet = ({
       } as any;
       assets.push(nativeAsset);
 
-      let stakedAsset;
-      if (accountBalanceByChainId.stakedBalance) {
+      if (
+        accountBalanceByChainId.stakedBalance &&
+        !hexToBN(accountBalanceByChainId.stakedBalance).isZero()
+      ) {
         stakedBalance = renderFromWei(accountBalanceByChainId.stakedBalance);
-        stakedAsset = {
+        const stakedAsset = {
           ...nativeAsset,
           nativeAsset,
           name: 'Staked Ethereum',