Updates cloudxr teleop known issue documentation

[tifchen-nvda]

Description

Updates cloudxr teleop doc to address

• [VDR][Isaac Lab][2.2] HW and SW compatibility requirements at the top
• [VDR][Isaac Lab][2.2] Collecting human demonstrations in VR still presents a learning curve
• [Isaac-Sim 5.0 rc8][Isaac-Lab 2.2 internal][Mimic] XR_ERROR_INSTANCE_LOST in xrPollEvent
• NV_GPU_INDEX issues

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context.
List any dependencies that are required for this change.

Fixes # (issue)

• [VDR][Isaac Lab][2.2] HW and SW compatibility requirements at the top
• [VDR][Isaac Lab][2.2] Collecting human demonstrations in VR still presents a learning curve
• [Isaac-Sim 5.0 rc8][Isaac-Lab 2.2 internal][Mimic] XR_ERROR_INSTANCE_LOST in xrPollEvent

Type of change

• Documentation update

Checklist

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there