Robustify waiting logic in e2e test (#9704)

* Robustify waiting for popup to open

Co-authored-by: Mark Stacey <markjstacey@gmail.com>

test/e2e/metamask-ui.spec.js

@@ -772,9 +772,8 @@ describe('MetaMask', function () {
       await driver.delay(regularDelayMs * 2)
 
       await driver.clickElement(By.xpath(`//button[contains(text(), 'Create Token')]`))
-      await driver.delay(largeDelayMs)
+      windowHandles = await driver.waitUntilXWindowHandles(3)
 
-      windowHandles = await driver.getAllWindowHandles()
       const popup = windowHandles[2]
       await driver.switchToWindow(popup)
       await driver.delay(regularDelayMs)

test/e2e/webdriver/driver.js

@@ -124,10 +124,11 @@ class Driver {
 
   async waitUntilXWindowHandles (x, delayStep = 1000, timeout = 5000) {
     let timeElapsed = 0
+    let windowHandles = []
     while (timeElapsed <= timeout) {
-      const windowHandles = await this.driver.getAllWindowHandles()
+      windowHandles = await this.driver.getAllWindowHandles()
       if (windowHandles.length === x) {
-        return
+        return windowHandles
       }
       await this.delay(delayStep)
       timeElapsed += delayStep