Only change floors in GridMap editor when holding Ctrl/Cmd, not Shift

The Shift modifier frequently interfered with freelook's speed modifier,
which led to the floor level being accidentally changed.

modules/gridmap/editor/grid_map_editor_plugin.cpp

@@ -608,13 +608,13 @@ EditorPlugin::AfterGUIInput GridMapEditor::forward_spatial_input_event(Camera3D
 	Ref<InputEventMouseButton> mb = p_event;
 
 	if (mb.is_valid()) {
-		if (mb->get_button_index() == MouseButton::WHEEL_UP && (mb->is_command_or_control_pressed() || mb->is_shift_pressed())) {
+		if (mb->get_button_index() == MouseButton::WHEEL_UP && (mb->is_command_or_control_pressed())) {
 			if (mb->is_pressed()) {
 				floor->set_value(floor->get_value() + mb->get_factor());
 			}
 
 			return EditorPlugin::AFTER_GUI_INPUT_STOP; // Eaten.
-		} else if (mb->get_button_index() == MouseButton::WHEEL_DOWN && (mb->is_command_or_control_pressed() || mb->is_shift_pressed())) {
+		} else if (mb->get_button_index() == MouseButton::WHEEL_DOWN && (mb->is_command_or_control_pressed())) {
 			if (mb->is_pressed()) {
 				floor->set_value(floor->get_value() - mb->get_factor());
 			}
@@ -753,7 +753,7 @@ EditorPlugin::AfterGUIInput GridMapEditor::forward_spatial_input_event(Camera3D
 
 	Ref<InputEventPanGesture> pan_gesture = p_event;
 	if (pan_gesture.is_valid()) {
-		if (pan_gesture->is_alt_pressed() && (pan_gesture->is_command_or_control_pressed() || pan_gesture->is_shift_pressed())) {
+		if (pan_gesture->is_alt_pressed() && pan_gesture->is_command_or_control_pressed()) {
 			const real_t delta = pan_gesture->get_delta().y * 0.5;
 			accumulated_floor_delta += delta;
 			int step = 0;