Move scrollbars in scrollable tabs to the top

[hellcp-work]

This is a bit of a hacky solution, to the problem of the scrollbar in scrollable tabs taking up around the third of clickable links. Moving it to the top moves it into the top padding, making the problem a little bit less annoying.

This requires some discussion and a bit more testing, so that we are sure it doesn't break in some spectacular way

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.22%. Comparing base (ff93a67) to head (dbe6fe4). Report is 4264 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #13412      +/-   ##
==========================================
+ Coverage   88.19%   88.22%   +0.02%     
==========================================
  Files         711      711              
  Lines       24230    24230              
==========================================
+ Hits        21370    21376       +6     
+ Misses       2860     2854       -6