Active nav drawer items cause user tour to be placed behind nav drawer

Hi,

we've encountered that the user tours dialogue is not displayed correctly if a step references an active the navdrawer item.
The dialogue will be displayed behind the nav drawer so that the step information cannot be read anymore.

Here are the steps to reproduce (with screenshots - since Moodle 3.6):

1. Login as admin
2. Go to User Tours admin page (/admin/tool/usertours/configure.php)
3. Click on the tour "New Messaging System"
4. Add a new step with these settings:
   1. Target type: Selector
   2. CSS selector: .list-group-item[data-key="coursehome"]
   3. Title: Course menu
   4. Content: Your current course menu is placed within this section of the left menu.
   5. Show with backdrop: No
5. Save the changes
6. Move the new step right above the step called "End of tour"
7. Then add another step for example for the node .list-group-item[data-key="participants"] and move it directly above the step "End of tour", too.
8. Go to a course
9. Wait if the user tour starts automatically or restart the tour by using the link "Reset user tour on this page" in the footer
10. Click next until the step with the course home node is reached
    => See that the dialogue is hidden behind the nav drawer
    
11. Click next
    => Confirm that the other node in the nav drawer is displayed correctly.
    

Best, Kathrin