Undo in sound cue editor does not undo looping changes.

When using undo in the Sound Cue Editor to undo the looping check the editor switches focus to the output node and does not undo the looping check.

Setup:

1. Open editor using UE4Editor.exe QAGame
2. Import all of the surround audio files from UE4\Engine\Content\NotForLicensees\QA\Import_Test_Assets\Audio

Repro:

1. Right click on SurroundTest_51Test and select "create cue".
2. Double click on the newly created cue to open its editor.
3. Select the Wave Player node and check the looping box.
4. Ctrl+Z to undo and go back to the Wave Player node.

Result: The looping box is still checked.

Expected Result: The looping box is unchecked.