Fix move operator for WUPSConfigItem

include/wups/config/WUPSConfigCategory.h

@@ -20,7 +20,8 @@ public:
 
     WUPSConfigCategory &operator=(WUPSConfigCategory &&src) noexcept {
         if (this != &src) {
-            src.mHandle = {};
+            this->mHandle = src.mHandle;
+            src.mHandle   = {};
         }
         return *this;
     }

include/wups/config/WUPSConfigItem.h

@@ -21,7 +21,8 @@ public:
 
     WUPSConfigItem &operator=(WUPSConfigItem &&src) noexcept {
         if (this != &src) {
-            src.mHandle = {};
+            this->mHandle = src.mHandle;
+            src.mHandle   = {};
         }
         return *this;
     }

libraries/libwups/storageCPP.cpp

@@ -85,7 +85,7 @@ std::optional<WUPSStorageSubItem> WUPSStorageSubItem::GetOrCreateSubItem(std::st
     wups_storage_item outItem = {};
     err                       = WUPSStorageAPI_GetSubItem(mHandle, key.data(), &outItem);
     if (err == WUPS_STORAGE_ERROR_NOT_FOUND) {
-        return CreateSubItem(key);
+        return CreateSubItem(key, err);
     }
     return WUPSStorageSubItem(outItem);
 }