[partition] Disable one call to updateButtons()

- suggested by @abucodonosor, removing this one call seems
   to solve the data race for the device model.

src/modules/partition/gui/PartitionPage.cpp

@@ -581,7 +581,7 @@ void
 PartitionPage::onPartitionModelReset()
 {
     m_ui->partitionTreeView->expandAll();
-    updateButtons();
+    // updateButtons();
     updateBootLoaderIndex();
 }