With AtlasKit InlineDialog, the filmstrip z-index in vertical
filmstrip mode was adjusted as it had to be set to fixed position
for the dialogs to automagically be position fixed. This left
behind a regression where the filmstrip z-index was the same as
the video quality label, but came later in the dom, so the label
was not clickable. This commit modifies the z-index of the
vertical filmstrip to account for clicking of the video quality
label.