Reset cheats when importing S4/S6

src/openrct2/rct1/S4Importer.cpp

@@ -217,6 +217,8 @@ public:
 
         map_count_remaining_land_rights();
         research_determine_first_of_type();
+
+        CheatsReset();
     }
 
     bool GetDetails(scenario_index_entry* dst) override

src/openrct2/rct2/S6Importer.cpp

@@ -478,6 +478,8 @@ public:
         }
 
         research_determine_first_of_type();
+
+        CheatsReset();
     }
 
     void ImportRides()