Core/Units: Rename and change Get/SetVisibility to use a bool value instead of an unnecessary enum

Also replace some SetVisibility hacks to directly call UpdateObjectVisibility

--HG--
branch : trunk

src/server/game/Entities/Unit/Unit.cpp

@@ -12140,9 +12140,9 @@ bool Unit::isAlwaysDetectableFor(WorldObject const* seer) const
     return false;
 }
 
-void Unit::SetVisibility(UnitVisibility x)
+void Unit::SetVisible(bool x)
 {
-    if (x == VISIBILITY_OFF)
+    if (!x)
         m_serverSideVisibility.SetValue(SERVERSIDE_VISIBILITY_GM, SEC_GAMEMASTER);
     else
         m_serverSideVisibility.SetValue(SERVERSIDE_VISIBILITY_GM, SEC_PLAYER);
@@ -14700,13 +14700,13 @@ void Unit::SetContestedPvP(Player *attackedPlayer)
         player->addUnitState(UNIT_STAT_ATTACK_PLAYER);
         player->SetFlag(PLAYER_FLAGS, PLAYER_FLAGS_CONTESTED_PVP);
         // call MoveInLineOfSight for nearby contested guards
-        player->SetVisibility(player->GetVisibility());
+        UpdateObjectVisibility();
     }
     if (!hasUnitState(UNIT_STAT_ATTACK_PLAYER))
     {
         addUnitState(UNIT_STAT_ATTACK_PLAYER);
         // call MoveInLineOfSight for nearby contested guards
-        SetVisibility(GetVisibility());
+        UpdateObjectVisibility();
     }
 }