Changed the drop down class name and type of selection (#22727)

## **Description**

Fixing flaky test "Check if user select different type of secret
recovery phrase" modified the dropdown to specifically select the
element related to the secret recovery phrase, distinguishing it from
another dropdown used for language selection. Additionally, updated the
method to find elements by using a CSS selector for option selection.

## **Related issues**

#22714

Author: hjetpoluru

test/e2e/tests/onboarding.spec.js

@@ -117,12 +117,11 @@ describe('MetaMask onboarding @no-mmi', function () {
 
         await driver.clickElement('[data-testid="metametrics-no-thanks"]');
 
-        const dropdowns = await driver.findElements('select');
-        const dropdownElement = dropdowns[1];
-        await dropdownElement.click();
-        const options = await dropdownElement.findElements(
-          By.tagName('option'),
+        const dropdownElement = await driver.findElement(
+          '.import-srp__number-of-words-dropdown',
         );
+        await dropdownElement.click();
+        const options = await dropdownElement.findElements(By.css('option'));
 
         const iterations = options.length;