Slightly improve touch experience with interaction buttons

This doesn't change much visually with the new interaction button design done last month, but changes how it works internally.

Old

The touch targets are nicely sized, but as you can see the actual control is left aligned - meaning that it's very easy to touch the reblog button when you don't mean to.

New

The spacing has changed only marginally, but now the touch targets are more reasonably sized. The empty space above and below the interaction buttons on mobile are now put inside of the button too, making them even bigger without changing the overall spacing.

Also included is slight width improvements on mobile for the overflow menu (it was tiny even on this display) and enabling mobile improvements when tablet mode is enabled on desktop.