Fix overwriting of Node3D's local space transform

[mrushyendra]

Currently, when the DIRTY_LOCAL flag is set and a new transform is supplied using set_transform, the new transform may be overwritten the next time it is read, because the transform is reset using the Node3D's previous rotation and scale, even though the new transform should supersede those.

This PR modifies when the DIRTY_LOCAL flag is set to prevent a transform applied using set_transform being overwritten by any previous calls that changed the node's rotation, translation or scale.

Closes #43130

[Calinou]

cc @lawnjelly
(not sure who would be the best person to review this, but pinging just in case)

[akien-mga]

Sorry for the delay reviewing this.

This looks like it's no longer applicable in master as the code has changed significantly:

void Node3D::set_transform(const Transform3D &p_transform) {
        ERR_THREAD_GUARD;
        data.local_transform = p_transform;
        _replace_dirty_mask(DIRTY_EULER_ROTATION_AND_SCALE); // Make rot/scale dirty.

Would be good to check if the original bug is still reproducible in latest 4.1 betas, and if so how this change should be adapted for it.

Edit: From a quick test in #43130 (comment), the issue may not be reproducible in master, but still is in 3.x. So a version of this PR for 3.x could be useful (if @lawnjelly can confirm it's the right approach).

[lawnjelly]

Sorry I hadn't seen this before, I agree it does seem to make sense (for 3.x).

[akien-mga]

Redone for 3.x as #78439.