fix hardcoded raycast distance with viewport object picking

having the raycast distance hardcoded to `10000` caused input events
to not be registered in very large 3D scenes.

This resolves the issue by using the cameras far distance instead.
Creating the more predictable behavior of if an object is visible,
it will be picked by the viewport.

resolves: #49735

scene/main/viewport.cpp

@@ -715,10 +715,11 @@ void Viewport::_process_picking() {
 			if (camera_3d) {
 				Vector3 from = camera_3d->project_ray_origin(pos);
 				Vector3 dir = camera_3d->project_ray_normal(pos);
+				real_t far = camera_3d->far;
 
 				PhysicsDirectSpaceState3D *space = PhysicsServer3D::get_singleton()->space_get_direct_state(find_world_3d()->get_space());
 				if (space) {
-					bool col = space->intersect_ray(from, from + dir * 10000, result, Set<RID>(), 0xFFFFFFFF, true, true, true);
+					bool col = space->intersect_ray(from, from + dir * far, result, Set<RID>(), 0xFFFFFFFF, true, true, true);
 					ObjectID new_collider;
 					if (col) {
 						CollisionObject3D *co = Object::cast_to<CollisionObject3D>(result.collider);