WebXR: Fix inverted hand models

[jorodi]

Description

XRHandMeshModel sometimes becomes inverted when the hand models are created using XRHandModelFactory.

This doesn't happen when using OculusHandModel, so its method used in controller.addEventListener('disconnected') is used in XRHandModelFactory.

Reproduction

Device: Meta Quest 2, 3, 3s

Go to webxr_vr_handinput_profiles.html and select the mesh model. Then place both of your hands behind your head. Now move only one hand into view in front of your face. It should look inverted.

Note:
Try your left hand first to see if it gets inverted. If not, repeat by placing both hands behind your head and try your right. It seems the hand that gets inverted depends on the order of initialization.

[Mugen87]

@cabanier Does this change look good to you? The PR removes the controller.visible toggle so I hope the behavior is still the same as implemented via #23830.

[cabanier]

Yes, this looks ok. @jorodi , did you try picking up and dropping controllers with this PR?
Also try going to browser in overlay to ensure there are no stray hands.

[jorodi]

I tested those situations and didn't see any inverted or stray hands.

[jorodi]

Note, the Quest 2 has a known issue (for a few months to date) where on XR session initialization the hand or controller does not show.

Toggle the menu button to make the hand or controller appear as a work around.