[REG 3.2.2 -> 3.3.0] Horizontal scrollbar shrinks when changing vertical size

1. Open some projects to populate the "Recent Projects" section.
2. Go to Welcome mode, "Projects" tab.
   You'll see the list of projects. Because of the long paths the horizontal scrollbar make sense here in contrast to QTCREATORBUG-13385.
   
3. Drag the lower border of the window to resize the height a couple of times.
   The scrollbar becomes smaller and smaller.
   

This behavior is wrong in two ways:

1. Changing the height of the window should not change a horizontal scrollbar.
2. When changing the size and then changing it again, everything should look as it did before.

This worked correctly in Creator 3.2