Notebook tab can be switched on character info animation

[dobios]

After completing a page in the notebook, if the player switches tabs during the character info animation it stamps the page in question and breaks any subsequent char-info animation on that same page.

Ideally the player should not be able to close the notebook or change the tab during the animation.

NOTE: This bug does significantly speed up notebook completion, which is currently very useful when testing the game's ending and could be great for speed-running, so maybe it's best left unfixed for now.

This is left up to @astonedf to decide.