test: change browser homepage for e2e (#12839)

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## **Description**

In an effort to mitigate flakiness introduced by
#12019, the purpose of
this PR is to change the default browser home page from the portfolio
dapp to the test dapp.

## **Related issues**

Fixes:

## **Manual testing steps**

1. Go to this page...
2.
3.

## **Screenshots/Recordings**

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

### **Before**

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

### **After**

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

## **Pre-merge author checklist**

- [ ] 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).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] 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.

e2e/fixtures/fixture-builder.js

@@ -448,7 +448,7 @@ class FixtureBuilder {
           whitelist: [],
           tabs: [
             {
-              url: 'https://portfolio.metamask.io/explore?MetaMaskEntry=mobile/',
+              url: 'https://metamask.github.io/test-dapp/',
               id: 1692550481062,
             },
           ],

e2e/pages/Browser/ConnectedAccountsModal.js

@@ -89,7 +89,7 @@ class ConnectedAccountsModal {
   }
 
   async tapManagePermissionsButton() {
-    await TestHelpers.delay(3000);
+    await TestHelpers.delay(4000);
     await Gestures.waitAndTap(this.managePermissionsButton);
   }