ProjectExplorer: Avoid accidental changes on spinbox via mouse scroll

- Introduced an Utils::attachWheelBlocker() to disable mouse wheel events on the "Parallel Jobs" field.
- This prevents unintentional modifications when users inadvertently scroll over the input.

Change-Id: Iccb93305fbcf399cae683412078782b5ea9f4ad6
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/help/generalsettingspage.cpp

@@ -18,6 +18,7 @@
 
 #include <utils/algorithm.h>
 #include <utils/fileutils.h>
+#include <utils/guiutils.h>
 #include <utils/layoutbuilder.h>
 
 #include <QCheckBox>
@@ -105,6 +106,7 @@ GeneralSettingsPageWidget::GeneralSettingsPageWidget()
     zoomSpinBox->setSingleStep(10);
     zoomSpinBox->setValue(100);
     zoomSpinBox->setSuffix(Tr::tr("%"));
+    attachWheelBlocker(zoomSpinBox);
     antialiasCheckBox = new QCheckBox(Tr::tr("Antialias"));
 
     auto fontGroupBox = new QGroupBox(Tr::tr("Font"));