Fix share tabs
The share/embed tab bar used some hacks to disable MenuSelectWidget's
normal behavior of disappearing once a selection has been made; after
the last OOUI update this doesn't work anymore.
This commit makes some small changes to make it work again:
- replace .show() with .toggle() as the widget uses a custom show/hide mechanism now
- reorder some calls - .toggle() has no effect as long as the menu has no options
- disable autoHide which would hide the menu when the user clicks outside (didn't test if it is really needed but seemed reasonable)
Also undoes some CSS changes that came with the update.