EMI: Fix pause/unpause handling

Paused scripts were automatically unpaused:
- when entering/leaving the inventory
- when pausing/unpausing the game
- when changing the set

A paused script must not get unpaused after a
pause_scripts() / unpause_scripts() sequence (which stops/starts all
scripts).

This fixes the problem in the Lua bar, that the boats started to move
again once the kitchen was entered.