Steps to reproduce:
1. Open the attached user's project "StereoRenderTextureTest.zip"
2. Enter Play Mode with a Quest 1/2 attached using Link
3. Look at the 2 quads marked as "Left" and "Right". They will show an identical image or only the left one will show an image

Expected result: The left and right image is slightly different (stereo pair)
Actual results: Both images are the same using OpenXR, and only the left image is shown with OculusXR

Reproducible on: 2020.3.38f1, 2021.3.8f1, 2022.1.15f1, 2022.2.0b8, 2023.1.0a11

Reproducible on these devices:
VLNQA00415 - Oculus Quest 2 (Quest 2), CPU: Snapdragon XR2, GPU: Adreno 650, OS: 10
VLNQA00275 - Oculus Quest (Quest), CPU: Snapdragon 835 MSM8998, GPU: Adreno 540, OS: 10

Notes:
-Issue reproduces with both OpenXR and OculusXR plugins
-Customer comment "The ability to render stereo renderTextures in SPI would greatly benefit performance for making Mirrors/Portals and just general PlanarReflections."
-A Camera marked to render "Both" eyes renders only the centerEye to a renderTexture's TextureArray even if the renderTexture is made using XRSettings.eyeTextureDesc.
Only the first slice is filled with the centerEye result or both slices are filled (on quest native) but they're always showing the centerEye not the left and the right eye's viewpoint.