Removed unused imports in new embedding. (#9463)

Author: matthew-carroll

shell/platform/android/io/flutter/embedding/android/FlutterFragment.java

@@ -6,8 +6,6 @@
 
 import static android.content.ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW;
 
-import android.arch.lifecycle.Lifecycle;
-import android.arch.lifecycle.LifecycleOwner;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;

shell/platform/android/io/flutter/embedding/android/FlutterView.java

@@ -27,7 +27,6 @@
 
 import java.util.ArrayList;
 import java.util.HashSet;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;