Remove unused includes of Q[H/V]BoxLayout

Change-Id: Ia90b30b634281414268e00722771470f1e7b69c0
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/android/androidmanifesteditorwidget.h

@@ -18,7 +18,6 @@ class QDomDocument;
 class QDomElement;
 class QComboBox;
 class QPushButton;
-class QHBoxLayout;
 class QLabel;
 class QLineEdit;
 class QListView;