Editor freezes when force deleting a level created with Conversion Suffix

Once force delete is initiated, editor was still non-responsive ~10 minutes later and had to be closed from Task Manager. Upon reopening the project, the level is still present in Content Browser and can be opened without issue.

1. Open LandscapeMountains (copied over from //UE4/Main/Samples/Showcases/LandscapeMountains/) in 5.0-EA
2. From Project Settings > World Partition, set:
   • Enable World Partition = True
   • Enable Conversion Prompt = True
3. Open the LandscapeMap level and click Yes to convert
4. Convert with the following settings:
   • In Place = False
   • Verbose = True
5. When the editor restarts, from the Content Browser, delete LandscapeMap_WP
6. Select Force Delete

Result:

**Editor freezes.

Expected:

Level is deleted without issue.