Ignore actors siding with player in awarness check to allow training the sneaking or knowing whether player is detected by other actors in the siding actor line of sight

CHANGELOG.md

@@ -9,6 +9,7 @@
     Bug #6066: addtopic "return" does not work from within script. No errors thrown
     Bug #6101: Disarming trapped unlocked owned objects isn't considered a crime
     Bug #6115: Showmap overzealous matching
+    Bug #6133: Cannot reliably sneak or steal in the sight of the NPCs siding with player
 
 0.47.0
 ------

apps/openmw/mwmechanics/actors.cpp

@@ -2396,11 +2396,17 @@ namespace MWMechanics
             float radius = std::min(fSneakUseDist, mActorsProcessingRange);
             getObjectsInRange(position, radius, observers);
 
+            std::set<MWWorld::Ptr> sidingActors;
+            getActorsSidingWith(player, sidingActors);
+
             for (const MWWorld::Ptr &observer : observers)
             {
                 if (observer == player || observer.getClass().getCreatureStats(observer).isDead())
                     continue;
 
+                if (sidingActors.find(observer) != sidingActors.cend())
+                    continue;
+
                 if (world->getLOS(player, observer))
                 {
                     if (MWBase::Environment::get().getMechanicsManager()->awarenessCheck(player, observer))