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/Debugger/AssembleInstructionDialog.cpp

@@ -41,7 +41,6 @@ QString HtmlFormatErrorLine(const Common::GekkoAssembler::AssemblerError& err)
 AssembleInstructionDialog::AssembleInstructionDialog(QWidget* parent, u32 address, u32 value)
     : QDialog(parent), m_code(value), m_address(address)
 {
-  setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
   setWindowModality(Qt::WindowModal);
   setWindowTitle(tr("Instruction"));