Custom event parameter set to 0 by default

Default parameters do not appear to be retained for custom events. This was tested in 4.17 and the issue does not occur in 4.16. Appears to be a regression

1. Open the editor
2. Open the level blueprint
3. Create a custom event
4. Add an int parameter
5. Set the default to 123
6. Compile and save
7. Call the custom event in the same blueprint

Result: The default int will be zero for the called custom event
Expected: The default that was set in the details panel would reflected by the called custom event by default