When the target of a user tour is off-screen and needs to be scrolled to, it scroll too far and miss place the highlight box.

Step to reproduce:

• Go to Site Administration > Development > Make test course and create an "S" sized course
• Go to Site Administration > Appearance > User tours
• Disable all the default tours
• Import the attached test_tour_MDL-75838.json and enable the tour
• Log in as a student and access the test course.
• Confirm that the course heading is highlighted correctly.
• Click "Next (1/3)"
• Expected: The first section is highlighted correctly.
• Actual: the first section is highlighted, but misaligned.
• Click "Next (2/3)"
• Expected: The fourth section is highlighted correctly.
• Actual: the fourth section is highlighted, but misaligned.