Prevent update_shape from being called twice on first frame, thus speeding up CSG nodes load times.

[emanvidmaker]

due to logic oversight, update_shape can get queued twice to run on the first frame, making scenes csg shapes laggy to open/load in, with this redundant call.

This change makes sure that it cant queue twice by marking it as dirty as soon as possible, so it cant queue again.

---

Found out about the double queue behavior when i was making a benching tool for csg and logging functions calls.
Where i saw that "update_shape" gets called twice on scene load.

...
NOTIFICATION_READY --- 0 Microseconds
NOTIFICATION_TRANSFORM_CHANGED --- 7 Microseconds
CSGShape3D::_update_collision_faces --- 68733 Microseconds
CSGShape3D::update_shape --- 1672920 Microseconds
CSGShape3D::_update_collision_faces --- 67424 Microseconds
CSGShape3D::update_shape --- 127781 Microseconds
===-===FRAME 1 ===-===
===-===FRAME 2 ===-===
===-===FRAME 3 ===-===
===-===FRAME 4 ===-===
===-===FRAME 5 ===-===
...

A bit of code-base reading later, found out that "_make_dirty" 's logic can double queue it on specific but common scenario. Where its a root shape and not dirty it will call_deferred twice.

Old code: (macros removed for clarity)

void CSGShape3D::_make_dirty(bool p_parent_removing) {
    if ((p_parent_removing || is_root_shape()) && !dirty) {
        callable_mp(this, &CSGShape3D::update_shape).call_deferred(); // ...
    }

    if (!is_root_shape()) {
        parent_shape->_make_dirty();
    }
    else if (!dirty) {
        callable_mp(this, &CSGShape3D::update_shape).call_deferred();
    }
    dirty = true;
  
}

by setting dirty = true; earlier in the logic it prevents this double queue from happening and calls it once. (since the second queue up looks if dirty is false)

new code: (macros removed for clarity)

void CSGShape3D::_make_dirty(bool p_parent_removing) {
    if ((p_parent_removing || is_root_shape()) && !dirty) {
        callable_mp(this, &CSGShape3D::update_shape).call_deferred(); // ...
        dirty = true; // +++ new code, now the else if will fail if this ran and avoid a requeue
    }

    if (!is_root_shape()) {
        parent_shape->_make_dirty();
    }
    else if (!dirty) {
        callable_mp(this, &CSGShape3D::update_shape).call_deferred();
    }
    dirty = true;
 }

With this fix, it now logs like this:

...
NOTIFICATION_READY --- 0 Microseconds
NOTIFICATION_TRANSFORM_CHANGED --- 6 Microseconds
CSGShape3D::_update_collision_faces --- 67143 Microseconds
CSGShape3D::update_shape --- 1569224 Microseconds
===-===FRAME 1 ===-===
===-===FRAME 2 ===-===
===-===FRAME 3 ===-===
===-===FRAME 4 ===-===
===-===FRAME 5 ===-===
...

And noticeably reduces scene loading time a second or so, since update_shape can get laggy and now only calls once.