### 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)

set_positional_shadow_atlas_quadrant_subdiv(1, SHADOW_ATLAS_QUADRANT_SUBDIV_4);
	set_positional_shadow_atlas_quadrant_subdiv(2, SHADOW_ATLAS_QUADRANT_SUBDIV_16);
	set_positional_shadow_atlas_quadrant_subdiv(3, SHADOW_ATLAS_QUADRANT_SUBDIV_64);
	set_mesh_lod_threshold(mesh_lod_threshold);
	String id = itos(get_instance_id());
	input_group = "_vp_input" + id;
	gui_input_group = "_vp_gui_input" + id;
	unhandled_input_group = "_vp_unhandled_input" + id;
	shortcut_input_group = "_vp_shortcut_input" + id;
	unhandled_key_input_group = "_vp_unhandled_key_input" + id;
	// Window tooltip.
	gui.tooltip_delay = GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "gui/timers/tooltip_delay_sec", PROPERTY_HINT_RANGE, "0,5,0.01,or_greater"), 0.5);
#ifndef _3D_DISABLED
	set_scaling_3d_mode((Viewport::Scaling3DMode)(int)GLOBAL_GET("rendering/scaling_3d/mode"));
	set_scaling_3d_scale(GLOBAL_GET("rendering/scaling_3d/scale"));
	set_fsr_sharpness((float)GLOBAL_GET("rendering/scaling_3d/fsr_sharpness"));
	set_texture_mipmap_bias((float)GLOBAL_GET("rendering/textures/default_filters/texture_mipmap_bias"));
#endif 
	set_sdf_oversize(sdf_oversize); // Set to server.
}
Viewport::~Viewport() {
	// Erase itself from viewport textures.
	for (ViewportTexture *E : viewport_textures) {
		E->vp = nullptr;
	}
	ERR_FAIL_NULL(RenderingServer::get_singleton());
	RenderingServer::get_singleton()->free(viewport);
}
//
void SubViewport::set_size(const Size2i &p_size) {