fix(Core/Unit): Fix Arena Preparation aura being removed on player ac… (#16925)

fix(Core/Unit): Fix Arena Preparation aura being removed on player actions

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

@@ -4766,6 +4766,14 @@ void Unit::RemoveAura(AuraApplication* aurApp, AuraRemoveMode mode)
     {
         if (aurApp == iter->second)
         {
+            // Prevent Arena Preparation aura from being removed by player actions
+            // It's an invisibility spell so any interaction/spell cast etc. removes it.
+            // Should only be removed by the arena script, once the match starts.
+            if (aurApp->GetBase()->HasEffectType(SPELL_AURA_ARENA_PREPARATION))
+            {
+                return;
+            }
+
             RemoveAura(iter, mode);
             return;
         }