Fix overbright cubemaps (playcanvas#2342)

* fix overbright cubemaps

Fix webxr lint failure (playcanvas#2341)

* add XRHand to externs

Load gltf textures correctly (playcanvas#2327)

* handle images/textures correctly on load
* various glb fixes
* lint

Handle gltfTextures correctly and update process callbacks (playcanva…

…s#2318)

* handle gltfTextures correctly and update process callbacks to match
* add image callback to docs

revert changes to texture coordinate flipping for glb (playcanvas#2310)

Merge remote-tracking branch 'upstream/master'

Merge remote-tracking branch 'upstream/master'

[Fix] Changes to Attribute to location mapping (playcanvas#2292)

add mip table (playcanvas#2255)

[FIX] WebXR session support check (playcanvas#2210)

* Fixed WebXR session support check

* Please use comma notation here:
Used comma notation

Co-authored-by: Steven Yau <syau@snaphcat.com>