modify: remove border-right of SideNav component

Author: sota1235

browser/main/SideNav/SideNav.styl

@@ -1,7 +1,6 @@
 .root
   absolute top left bottom
   width $sideNav-width
-  border-right $ui-border
   background-color $ui-backgroundColor
   user-select none
   color $ui-text-color