Fix quick access letter conflict with Export and Export Tracks (#7927)

Update shortcut `T` for exporting Tracks, so that `x` is default export.

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Co-authored-by: Sotonye Atemie <sakertooth@gmail.com>
Co-authored-by: Andrew Wiltshire <62200778+AW1534@users.noreply.github.com>

src/gui/MainWindow.cpp

@@ -312,7 +312,7 @@ void MainWindow::finalize()
 					SLOT(onExportProject()),
 					combine(Qt::CTRL, Qt::Key_E));
 	project_menu->addAction( embed::getIconPixmap( "project_export" ),
-					tr( "E&xport Tracks..." ),
+					tr("Export &Tracks..."),
 					this,
 					SLOT(onExportProjectTracks()),
 					combine(Qt::CTRL, Qt::SHIFT, Qt::Key_E));