Core/Spells: Fixed implementation of SPELL_ATTR1_IMMUNITY_TO_HOSTILE_AND_FRIENDLY_EFFECTS and removed banish special cases that were neccessary because that attribute wasn't correctly supported

Port From (https://github.com/TrinityCore/TrinityCore/commit/c968dedfee59db53fc912ac166309f3d87470821)

Source/Game/Spells/Auras/Aura.cs

@@ -410,7 +410,7 @@ namespace Game.Spells
             return Global.ObjAccessor.GetUnit(m_owner, m_casterGuid);
         }
 
-        WorldObject GetWorldObjectCaster()
+        public WorldObject GetWorldObjectCaster()
         {
             if (GetCasterGUID().IsUnit())
                 return GetCaster();
@@ -2785,7 +2785,7 @@ namespace Game.Spells
                 if (!GetUnitOwner().IsInWorld)
                     continue;
 
-                if (GetUnitOwner().HasUnitState(UnitState.Isolated))
+                if (GetUnitOwner().HasAuraState(AuraStateType.Banished, GetSpellInfo(), caster))
                     continue;
 
                 List<WorldObject> units = new();