Fix editor crash in multi-window mode

Bug: 31236427
Test: manual - based on "steps to reproduce" in the bug.
Change-Id: Iea187b7b1389a9f8ebd4acfd603cf51376c22c11
diff --git a/src/com/android/contacts/editor/ContactEditorFragment.java b/src/com/android/contacts/editor/ContactEditorFragment.java
index 8762dc2..f10120c 100644
--- a/src/com/android/contacts/editor/ContactEditorFragment.java
+++ b/src/com/android/contacts/editor/ContactEditorFragment.java
@@ -520,6 +520,9 @@
 
         @Override
         public void startPhotoActivity(Intent intent, int requestCode, Uri photoUri) {
+            if (getActivity() == null) {
+                return;
+            }
             mRawContactIdRequestingPhoto = mEditor.getRawContactId();
             mCurrentPhotoHandler = this;
             mStatus = Status.SUB_ACTIVITY;