Remove invalid permanent effects

Fixes #8737 (closed).

Effects that are invalid for the given target (such as a bound weapon's Fortify Skill on a creature) are marked as removable with their remaining duration set to 0. For temporary effects this ensures the effect gets removed in the next update, but for permanent effects this doesn't do much of anything. As such we'll try to apply the effect again in the next frame, which incurs another attempt at playing sfx and vfx because the effect (truthfully) hasn't been marked as applied.

!4766 (merged) made CE enchantments behave more like everything else, exposing this issue. The other permanent effect types were probably already affected in 0.49. !4297 (merged) made 0 magnitude effects detectable through GetEffect, but neglected to make invalid effects detectable the same way. Not a regression, but this MR corrects it nonetheless. Note that applied effects are a subset of removable effects.