Tablet styling tweaks

* Make ToC's width auto so that it stays narrow when it can and expands
  if section names are long (consulted with Moiz)
* Every section after second section has extra line above section header
  which should get removed
* Remove vertical line next to section edit icons
* Article title and article action icons should be aligned (currently the
  latter are sitting a little lower than the former on the line)

Bug: 65201
Change-Id: Ia4a85d7e7abf75e9a18009d79b2ffeca04cf0c53