K2Node_GetEnumeratorName doesn't support bitmasks

This is almost identical to [Link Removed]. The difference is that we need a variant of UEnum::GetNameByValue that supports bitmasks. We'll likely have to run this by Core.

Issue 3:

1. Drag Issue3_BP into the level.
2. Start PIE.
3. Observe screen prints "None".
4. Expected behavior: screen prints "One | Two"