Return ILLEGAL_ARGUMENT for setting null callback

Bug: 299182872
Test: Run VTS with external USB camera
vts-tradefed
> run vts -m VtsAidlHalCameraProvider_TargetTest -t \
    PerInstance/CameraAidlTest#setCallback/0_android_hardware_camera_provider_ICameraProvider_external_0 \
    --logcat-on-failure --logcat-on-failure-size 8192000 \
    --bugreport-on-failure --screenshot-on-failure

Change-Id: I013e3770ddbdcf6475e0927449af6183dcc37a8e