Reverts workaround for fsd issue in XR app settings

[rwiltz]

Description

Previously a kit change caused a performance regression in IsaacLab. This has been resolved and now the work around can be reverted.

Type of change

• Bug fix (non-breaking change which fixes an issue)

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

[Mayankm96]

Please make sure the MR title reflects correctly the fix that is getting made. We want to avoid generic names to make it easier to generate release notes.

Also please be mindful of the ticks made on the checklist. I don't see any test or docs being added in the MR. Yet they have been ticked/