### Godot version

v4.1.stable.official [970459615]

### System information

Godot v4.1.stable - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1660 Ti (NVIDIA; 31.0.15.3598) - AMD Ryzen 7 3700X 8-Core Processor (16 Threads)

### Issue description

is_input_handled() is returning True, even though set_input_as_handled() has not been called.

Example:
`func _input_event(viewport, event, shape_idx):
	print(viewport.is_input_handled())`

Returns 'True', should return 'False'

### Steps to reproduce

1. Create a new project and add a Node2D as the root
2. Add a child Area2D node containing a CollisionShape2D and a Sprite2D
3. Either create the _input_event(viewport, event, shape_idx) or connect _on_input_event(viewport, event, shape_idx)
4. Print viewport.is_input_handled()
5. True is printed.

### Minimal reproduction project

[input_test.zip](https://github.com/godotengine/godot/files/12063748/input_test.zip)

gui.subwindow_drag_close_rect = close_rect;
					} else {
						gui.subwindow_drag = SUB_WINDOW_DRAG_MOVE;
					}
					gui.subwindow_drag_from = mb->get_position();
					gui.subwindow_drag_pos = sw.window->get_position();
					_sub_window_update(sw.window);
				} else {
					gui.subwindow_resize_mode = _sub_window_get_resize_margin(sw.window, mb->get_position());
					if (gui.subwindow_resize_mode != SUB_WINDOW_RESIZE_DISABLED) {
						if (gui.subwindow_focused != sw.window) {
							
							_sub_window_grab_focus(sw.window);
						}
						gui.subwindow_resize_from_rect = r;
						gui.subwindow_drag_from = mb->get_position();
						gui.subwindow_drag = SUB_WINDOW_DRAG_RESIZE;
						click_on_window = sw.window;
					}
				}
			}
			if (!click_on_window && r.has_point(mb->get_position())) {
				
				if (gui.subwindow_focused != sw.window) {
					
					_sub_window_grab_focus(sw.window);
				}
				click_on_window = sw.window;
			}
			if (click_on_window) {