Adding t() function in UiHelperTrait::drupalLogin()

Implements solution similar to #13 as MR.

This will allow user to use `drupalLogin` function when site is set to locale other than English.

## Test

1. Install drupal site with Japanese locale. IE.

drush si --locale=ja

2. Use function in functional Test

$this->author = $this->createUser([], NULL);
$this->drupalLogin($this->author, 'ログイン');

Since the tests are failing, this should remain "Needs work" till the tests are green.

core/modules/ckeditor5/tests/src/Traits/SynchronizeCsrfTokenSeedTrait.php trait uses drupalLogin which expects the text "Log in".

Rerolled for 10.2.x because the SubmitForm function no longer accepts a TranslatableMarkup.

TypeError: Behat\Mink\Element\TraversableElement::findButton(): Argument #1 ($locator) must be of type string, Drupal\Core\StringTranslation\TranslatableMarkup given