Core/Reputation: Fix reaction with rival factions

Closes #9469
Ref #20661

src/server/game/Reputation/ReputationMgr.cpp

@@ -463,8 +463,8 @@ void ReputationMgr::SetAtWar(RepListID repListID, bool on)
 
 void ReputationMgr::SetAtWar(FactionState* faction, bool atWar) const
 {
-    // not allow declare war to own faction
-    if (atWar && (faction->Flags & FACTION_FLAG_PEACE_FORCED))
+    // Do not allow to declare war to our own faction. But allow for rival factions (eg Aldor vs Scryer).
+    if (atWar && (faction->Flags & FACTION_FLAG_PEACE_FORCED) && !(faction->Flags & FACTION_FLAG_RIVAL))
         return;
 
     // already set