fix(liveness): Prevent crash on detachPreviewSurface is context is null (#255)

Co-authored-by: Matt Creaser <[email protected]>

Author: Tyler Roach

liveness/src/main/java/com/amplifyframework/ui/liveness/camera/OpenGLRenderer.java

@@ -325,7 +325,11 @@ public ListenableFuture<Void> detachPreviewSurface() {
                 mExecutor.execute(
                         () -> {
                             if (!mIsShutdown) {
-                                setWindowSurface(mAdditionalContext, null);
+                                if (mAdditionalContext != 0) {
+                                    setWindowSurface(mAdditionalContext, null);
+                                } else if (DEBUG) {
+                                    Log.d(TAG, "!!! mAdditionalContext null during detachPreviewSurface");
+                                }
                                 mAdditionalTransformation.mSurfaceSize = null;
                             }
                             completer.set(null);