fix: flaky test flaky `Request Queuing for Multiple Dapps and Txs on …

…different networks. should switch to the dapps network automatically when handling sendTransaction calls` (#24741)

## **Description**
This PR fixes the flaky test `Request Queuing for Multiple Dapps and Txs
on different networks. should switch to the dapps network automatically
when handling sendTransaction calls `.

The problem is that sometimes when we call the `const
currentWindowHandles = await driver.getAllWindowHandles` there is still
the previous popup open, meaning that we get the total count of 4
windows.

Right after that, we trigger a send `await
driver.clickElement('#sendButton');` and now we wait for the
windowHandles to be `currentWindowHandles + 1` meaning we wait until we
have 5 windows. However this will never happen as we should wait for 4
windows instead, but the previous windowCount was considering the
previous popup, resulting in 1 more window in total.

```
  const currentWindowHandles = await driver.getAllWindowHandles();
  await driver.clickElement('#sendButton');
  const newWindowHandles = await driver.waitUntilXWindowHandles(
    process.env.ENABLE_MV3
      ? currentWindowHandles.length
      : currentWindowHandles.length + 1,
```

The proposed fix is to hardcode the expect number of windows directly,
as we know how many there should be and we do this in the majority of
the tests. There could be alternative approaches,
- wait for a condition: though in this case the condition of having
switched networks is already met in the wallet, so there doesn't seem to
be another condition to wait for 🤔
- add a delay



## **Related issues**

Fixes: the third item of this list
#24603

## **Manual testing steps**

1. Run the test several times `yarn test:e2e:single
test/e2e/tests/request-queuing/ui.spec.js --browser=chrome
--leave-running --retryUntilFailure --retries=10`
2. Check ci jobs

## **Screenshots/Recordings**
See how at one point, we get current windows as 4 (we expected 3)
because the popup was still not closed and the next time we trigger a
tx, we would expect 4+1, which will never happen.


https://github.com/MetaMask/metamask-extension/assets/54408225/a3eb7f74-cf2c-43ba-a5bb-0835544b448c




## **Pre-merge author checklist**

- [X] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.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-extension/blob/develop/.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.

test/e2e/tests/request-queuing/ui.spec.js

@@ -64,6 +64,9 @@ async function openDappAndSwitchChain(driver, dappUrl, chainId) {
 
 async function selectDappClickSendGetNetwork(driver, dappUrl) {
   await driver.switchToWindowWithUrl(dappUrl);
+  // Windows: MetaMask, TestDapp1, TestDapp2
+  const expectedWindowHandles = 3;
+  await driver.waitUntilXWindowHandles(expectedWindowHandles);
   const currentWindowHandles = await driver.getAllWindowHandles();
   await driver.clickElement('#sendButton');