Magic effects are updated once before applying when resting

Fixing #7970.
When the player was resting, all their magic effects were applied throughout
the rest duration, including the effects for already removed spells, which
were applied once more before removal.
This commit calls an update before that applying, so that these removed
spells are executed and removed and only then the real duration-long
execution of remaining magic effects takes place.

CHANGELOG.md

@@ -172,6 +172,7 @@
     Bug #7901: Editor: Teleport-related fields shouldn't be editable if a ref does not teleport
     Bug #7908: Key bindings names in the settings menu are layout-specific
     Bug #7943: Using "addSoulGem" and "dropSoulGem" commands to creatures works only with "Weapon & Shield" flagged ones
+    Bug #7970: Difference of GetPCSleep (?) behavior between vanilla and OpenMW
     Feature #2566: Handle NAM9 records for manual cell references
     Feature #3537: Shader-based water ripples
     Feature #5173: Support for NiFogProperty

apps/openmw/mwmechanics/actors.cpp

@@ -1879,6 +1879,9 @@ namespace MWMechanics
                     > actorsProcessingRange * actorsProcessingRange)
                 continue;
 
+            // Get rid of effects pending removal so they are not applied when resting
+            updateMagicEffects(actor.getPtr());
+
             adjustMagicEffects(actor.getPtr(), duration);
 
             MWRender::Animation* animation = MWBase::Environment::get().getWorld()->getAnimation(actor.getPtr());