I tried upgrading the android/camera-samples (https://github.com/android/camera-samples) project but got errors because the `OutputFileResults#getSavedUri` from `OnImageSavedCallback#onImageSaved` returned a null.

CAMERAX VERSION 1.0.0-alpha10

CAMERA APPLICATION NAME AND VERSION: (Settings > Apps > (app name) > version)

ANDROID OS BUILD NUMBER: sdk_google_phone_x86-eng 5.0.2 LSY66K 5523115 test-keys

DEVICE NAME: sdk_google_phone_x86 (I also had the issue on my Pixel 4XL)

DESCRIPTION:

STEPS TO REPRODUCE:
1. Clone my modified version of `camera-samples`
```
git clone git@github.com:SalvatoreT/camera-samples.git
```
2. Run the app in Android Studio.
3. Take a photo.

OBSERVED RESULTS:
You'll see the following in logcat.

```
FATAL EXCEPTION: main
Process: com.android.example.cameraxbasic, PID: 6623
kotlin.KotlinNullPointerException
at com.android.example.cameraxbasic.fragments.CameraFragment$imageSavedListener$1.onImageSaved(CameraFragment.kt:196)
at androidx.camera.core.ImageCapture$2.onImageSaved(ImageCapture.java:642)
at androidx.camera.core.ImageSaver$1.run(ImageSaver.java:242)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
```

EXPECTED RESULTS: Not a crash.

REPRODUCIBILITY: every time

CODE FRAGMENTS: Here are the changes I made. https://github.com/SalvatoreT/camera-samples/commit/6d86c01d02daac01513cdce1d124131b1f22289d