I found that the GVR package, used by both Google Cardboard and Daydream, is always removed from the manifest.json if Daydream is disabled/removed from the XR SDK list. This causes problems when Cardboard is still in the list as it still depends on GVR. Also, I'm not confident that the GVR package is consistently added if you add Cardboard in, which is what I would expect.

Repro:
1. Start with Cardboard and Daydream sdks in list. Verify GVR packages is in manifest.json file
2. Remove Daydream

Expected: GVR package is still in manifest.json for Cardboard to use
Actual: GVR is removed, causing issues running Cardboard

Secondary repro:
1. Start with Cardboard and None sdks in the list
2. manually remove the gvr package from the manifest.json file, save
3. Go back to Editor and remove Cardboard from sdk list, leaving only None.
4. Add Cardboard back into sdk list

Expected: GVR package is added into manifest.json file
Actual: GVR package is not consistently added to manifest