TaskTree: Change the signature of storage handlers

The handlers for TaskTree::onStorage{Setup,Done}(...)
took a pointer to the storage struct. Take a reference instead.
This is in line with tasks setup/done/error handlers.

Change-Id: I8ff18c250f0fbbcd8210ec304e34232e842831fc
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/libs/solutions/tasking/tasktree.h

@@ -437,7 +437,7 @@ private:
     StorageVoidHandler wrapHandler(StorageHandler &&handler) {
         return [=](void *voidStruct) {
             StorageStruct *storageStruct = static_cast<StorageStruct *>(voidStruct);
-            std::invoke(handler, storageStruct);
+            std::invoke(handler, *storageStruct);
         };
     }