test: fix flaky snap signature test (#29480)

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## **Description**

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## **Related issues**

Fixes:
[#29380](#29380)

## **Manual testing steps**

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test/e2e/helpers.js

@@ -722,7 +722,7 @@ async function clickSignOnSignatureConfirmation({
   if (snapSigInsights) {
     // there is no condition we can wait for to know the snap is ready,
     // so we have to add a small delay as the last alternative to avoid flakiness.
-    await driver.delay(regularDelayMs);
+    await driver.delay(largeDelayMs);
   }
   await driver.waitForSelector(
     { text: 'Sign', tag: 'button' },

test/e2e/snaps/test-snap-siginsights.spec.js

@@ -175,8 +175,13 @@ describe('Test Snap Signature Insights', function () {
           // switch back to MetaMask window and switch to tx insights pane
           await driver.switchToWindowWithTitle(WINDOW_TITLES.Dialog);
 
+          await driver.waitForSelector(
+            '[data-testid="signature-request-scroll-button"]',
+          );
           // click down arrow
-          await driver.clickElementSafe('.fa-arrow-down');
+          await driver.clickElementSafe(
+            '[data-testid="signature-request-scroll-button"]',
+          );
 
           // wait for and click sign
           await clickSignOnSignatureConfirmation({
@@ -223,7 +228,12 @@ describe('Test Snap Signature Insights', function () {
           await driver.switchToWindowWithTitle(WINDOW_TITLES.Dialog);
 
           // click down arrow
-          await driver.clickElementSafe('.fa-arrow-down');
+          await driver.waitForSelector(
+            '[data-testid="signature-request-scroll-button"]',
+          );
+          await driver.clickElementSafe(
+            '[data-testid="signature-request-scroll-button"]',
+          );
 
           // wait for and click sign
           await clickSignOnSignatureConfirmation({