refactor: Remove most raw accesses into Application (#5104)

src/controllers/highlights/HighlightModel.cpp

@@ -509,7 +509,7 @@ void HighlightModel::customRowSetData(const std::vector<QStandardItem *> &row,
         break;
     }
 
-    getApp()->windows->forceLayoutChannelViews();
+    getIApp()->getWindows()->forceLayoutChannelViews();
 }
 
 }  // namespace chatterino

src/controllers/highlights/UserHighlightModel.cpp

@@ -113,7 +113,7 @@ void UserHighlightModel::customRowSetData(
         break;
     }
 
-    getApp()->windows->forceLayoutChannelViews();
+    getIApp()->getWindows()->forceLayoutChannelViews();
 }
 
 // row into vector item