### 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)

List<ObjectID> to_erase;
	for (const KeyValue<ObjectID, uint64_t> &E : physics_2d_mouseover) {
		if (!p_clean_all_frames && E.value == p_frame_reference) {
			continue;
		}
		Object *o = ObjectDB::get_instance(E.key);
		if (o) {
			CollisionObject2D *co = Object::cast_to<CollisionObject2D>(o);
			if (co && co->is_inside_tree()) {
				if (p_clean_all_frames && p_paused_only && co->can_process()) {
					continue;
				}
				co->_mouse_exit();
			}
		}
		to_erase.push_back(E.key);
	}
	while (to_erase.size()) {
		physics_2d_mouseover.erase(to_erase.front()->get());
		to_erase.pop_front();
	}
	
	List<Pair<ObjectID, int>> shapes_to_erase;
	for (KeyValue<Pair<ObjectID, int>, uint64_t> &E : physics_2d_shape_mouseover) {
		if (!p_clean_all_frames && E.value == p_frame_reference) {
			continue;
		}
		Object *o = ObjectDB::get_instance(E.key.first);
		if (o) {
			CollisionObject2D *co = Object::cast_to<CollisionObject2D>(o);