Add wrapper function to disable hotkeys for QFileDialog

Previously, if you have "Hotkeys Require Window Focus" disabled, you could repeatedly use the "Open" hotkey, for example, to stack File Open windows over top of each other over and over.

This commit allows the hotkey manager to disable/enable on QFileDialog creation and destruction.

Source/Core/DolphinQt/ConvertDialog.cpp

@@ -11,7 +11,6 @@
 
 #include <QCheckBox>
 #include <QComboBox>
-#include <QFileDialog>
 #include <QGridLayout>
 #include <QGroupBox>
 #include <QLabel>
@@ -26,6 +25,7 @@
 #include "DiscIO/Blob.h"
 #include "DiscIO/ScrubbedBlob.h"
 #include "DiscIO/WIABlob.h"
+#include "DolphinQt/QtUtils/DolphinFileDialog.h"
 #include "DolphinQt/QtUtils/ModalMessageBox.h"
 #include "DolphinQt/QtUtils/ParallelProgressDialog.h"
 #include "UICommon/GameFile.h"
@@ -374,7 +374,7 @@ void ConvertDialog::Convert()
 
   if (m_files.size() > 1)
   {
-    dst_dir = QFileDialog::getExistingDirectory(
+    dst_dir = DolphinFileDialog::getExistingDirectory(
         this, tr("Select where you want to save the converted images"),
         QFileInfo(QString::fromStdString(m_files[0]->GetFilePath())).dir().absolutePath());
 
@@ -383,7 +383,7 @@ void ConvertDialog::Convert()
   }
   else
   {
-    dst_path = QFileDialog::getSaveFileName(
+    dst_path = DolphinFileDialog::getSaveFileName(
         this, tr("Select where you want to save the converted image"),
         QFileInfo(QString::fromStdString(m_files[0]->GetFilePath()))
             .dir()