DolphinQt: Remove redundant window hints

Remove window hints clearing the flag Qt::WindowContextHelpButtonHint,
which is already off by default in Qt 6.

In Qt 5 this flag was set by default for QDialogs, and on Windows put a
? button in the corner of the title bar allowing users to activate Qt's
QWhatsThis help system for a given widget. Since we don't set that text
the ? button was useless and so we hid it manually.

Source/Core/DolphinQt/NANDRepairDialog.cpp

@@ -27,7 +27,6 @@ NANDRepairDialog::NANDRepairDialog(const WiiUtils::NANDCheckResult& result, QWid
     : QDialog(parent)
 {
   setWindowTitle(tr("NAND Check"));
-  setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
   setWindowIcon(Resources::GetAppIcon());
 
   QVBoxLayout* main_layout = new QVBoxLayout();