MDL-66979 scorm: Increase behat window size

On Firefox there can be some issues with ensuring that all nodes are
visible in order to click them.

This is likely an upstream geckodriver bug and not one that can be
easily addressed across all of Moodle.

In this instance the "Next" button is just outside the Visible Window,
but it is in an iFrame which is fully visible. In this situation
Firefox is unable to click the button but does not error.

mod/scorm/tests/behat/save_progress_on_unload.feature

@@ -15,6 +15,7 @@ Feature: Confirm progress gets saved on unload events
       | user | course | role |
       | teacher1 | C1 | editingteacher |
       | student1 | C1 | student |
+    And I change window size to "large"
 
   @javascript
   Scenario: Test progress gets saved correctly when the user navigates away from the scorm activity