Spawn controller entities

[SafariMonkey]

bevy_oxr queries for entities with:

        &mut Transform,
        Option<&mut AimPose>,
        With<OpenXRRightController>,
        Without<OpenXRLeftController>,

(and with With/Without swapped) and it crashes when it unwraps that query if none exist. It probably shouldn't be unwrapping, but that needs actual design decisions to fix, and meanwhile, this fixes the crash.