Fix Java null pointer exception

Author: gspencergoog

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

@@ -368,6 +368,7 @@ private boolean handleEventImpl(
     output.physicalKey = physicalKey;
     output.character = character;
     output.synthesized = false;
+    output.deviceType = KeyData.DeviceType.kKeyboard;
 
     sendKeyEvent(output, onKeyEventHandledCallback);
     for (final Runnable postSyncEvent : postSynchronizeEvents) {
@@ -384,6 +385,7 @@ private void synthesizeEvent(boolean isDown, Long logicalKey, Long physicalKey,
     output.physicalKey = physicalKey;
     output.character = null;
     output.synthesized = true;
+    output.deviceType = KeyData.DeviceType.kKeyboard;
     if (physicalKey != 0 && logicalKey != 0) {
       updatePressingState(physicalKey, isDown ? logicalKey : null);
     }