chore(cleanup): don't std::move for return statement

std::moveing prevents RVO, and even in cases where RVO can't take place, move
will be used if possible.

Fix #6011

src/persistence/profile.cpp

@@ -117,7 +117,7 @@ std::unique_ptr<ToxEncrypt> loadToxData(const QString& password, const QString&
 
     saveFile.close();
     error = LoadToxDataError::OK;
-    return std::move(tmpKey);
+    return tmpKey;
 fail:
     saveFile.close();
     return nullptr;