We should make sure that changing IDL for XRSessionCreationOptions results in a compile-time error in convertIdlOptionsToMojo to ensure that we inspect all the relevant fields when creating XRSessionOptions.

One way to achieve that would be to call XRSessionOptions::New() overload that explicitly takes 4 parameters (at the time of writing) - this would cause a compiler break every time a mojo interface gets regenerated and give the developer an opportunity to make sure that the conversion from IDL to mojo happens the way it should.